Phonological development
Encyclopedia
Sound is at the beginning of language learning. Children have to learn to distinguish different sounds and to segment the speech stream they are exposed to into units – eventually meaningful units – in order to acquire words and sentences. So, if an infant hears the sound sequence “thisisacup,” it has to learn to segment this stream into the distinct units “this”, “is”, “a”, and “cup.” Once the child is able to extract the sequence “cup” from the speech stream it has to assign a meaning to this word. Furthermore, the child has to be able to distinguish the sequence “cup” from “cub” in order to learn that these are two distinct words with different meanings. Finally, the child has to learn to produce these words.
The acquisition of native language phonology
begins in the womb and isn’t completely adult-like until the teenage years. Perceptual abilities (such as being able to segment “thisisacup” into four individual word units) usually precede production and thus aid the development of speech production.
features.
Infants as young as 1 month perceive some speech sounds as speech categories (they display categorical perception
of speech). For example, the sounds /b/ and /p/ differ in the amount of breathiness that follows the opening of the lips. Using a computer generated continuum in breathiness between /b/ and /p/, Eimas et al. (1971) showed that English-learning infants paid more attention to differences near the boundary between /b/ and /p/ than to equal-sized differences within the /b/-category or within the /p/-category. Their measure, monitoring infant sucking-rate, became a major experimental method for studying infant speech perception.
Infants up to 10–12 months can distinguish not only native sounds but also nonnative contrasts. Older children and adults lose the ability to discriminate some nonnative contrasts. Thus, it seems that exposure to one’s native language causes the perceptual system to be restructured. The restructuring reflects the system of contrasts in the native language.
to adult-directed speech. Whereas 1-month-olds only exhibit this preference if the full speech signal is played to them, 4-month-old infants prefer infant-directed speech even when just the pitch contour
s are played. This shows that between 1 and 4 months of age, infants improve in tracking the suprasegmental
info in the speech directed at them. By 4 months, finally, infants have learned which features they have to pay attention to at the suprasegmental level.
, such as an /i/ spoken by a male versus a female speaker, as members of the same phonological category /i/.
Infants are able to extract meaningful distinctions in the language they are exposed to from statistical properties of that language. For example, if English-learning infants are exposed to a prevoiced /d/ to voiceless
unaspirated
/t/ continuum (similar to the /d/ - /t/ distinction in Spanish) with the majority of the tokens occurring near the endpoints of the continuum, i.e., showing extreme prevoicing versus long voice onset times (bimodal distribution
) they are better at discriminating these sounds than infants who are exposed primarily to tokens from the center of the continuum (unimodal distribution).
These results show that at the age of 6 months infants are sensitive to how often certain sounds occur in the language they are exposed to and they can learn which cues are important to pay attention to from these differences in frequency of occurrence. In natural language exposure this means typical sounds in a language (such as prevoiced /d/ in Spanish) occur often and infants can learn them from mere exposure to them in the speech they hear. All of this occurs before infants are aware of the meaning of any of the words they are exposed to, and therefore the phenomenon of statistical learning has been used to argue for the fact that infants can learn sound contrasts without meaning being attached to them.
At 6 months, infants are also able to make use of prosodic
features of the ambient language to break the speech stream they are exposed to into meaningful units, e.g., they are better able to distinguish sounds that occur in stressed
vs. unstressed syllable
s. This means that at 6 months infants have some knowledge of the stress
patterns in the speech they are exposed and they have learned that these patterns are meaningful.
) stress
pattern, which is the most common stress pattern in the English language, but they were not able to segment out words that follow a weak-strong pattern. In the sequence ‘guitar is’ these infants thus heard ‘taris’ as the word-unit because it follows a strong-weak pattern.
The process that allows infants to use prosodic
cues in speech input to learn about language structure has been termed “prosodic bootstrapping
”.
and phonotactic
patterns alone, i.e., without the help of prosodic
cues. They seem to have learned their native language’s phonotactics
, i.e., which combinations of sounds are possible in the language.
in their native language. Their perceptual system has been tuned to the contrasts relevant in their native language.
As for word comprehension, Fenson et al. (1994) tested 10-11-month-old children’s comprehension vocabulary size and found a range from 11 words to 154 words. At this age, children normally have not yet begun to speak and thus have no production vocabulary. So clearly, comprehension vocabulary develops before production vocabulary.
These earliest vocalizations include crying and vegetative sounds such as breathing, sucking or sneezing. For these vegetative sounds, infants’ vocal cords
vibrate and air passes through their vocal apparatus, thus familiarizing infants with processes involved in later speech production.
Infants produce cooing sounds when they are content. Cooing is often triggered by social interaction with caregivers and resembles the production of vowels.
Infants produce a variety of vowel- and consonant-like sounds that they combine into increasingly longer sequences. The production of vowel
sounds (already in the first 2 months) precedes the production of consonant
s, with the first back consonants (e.g., [g], [k]) being produced around 2–3 months, and front consonants (e.g., [m], [n], [p]) starting to appear around 6 months of age.
As for pitch contour
s in early infant utterances, infants between 3 and 9 months of age produce primarily flat, falling and rising-falling contours. Rising pitch contour
s would require the infants to raise subglottal
pressure during the vocalization or to increase vocal fold
length or tension at the end of the vocalization, or both. At 3 to 9 months infants don’t seem to be able to control these movements yet.
Reduplicated babbling
contains consonant-vowel (CV) syllable
s that are repeated in reduplicated series of the same consonant
and vowel
(e.g., [bababa]). At this stage, infants’ productions resemble speech much more closely in timing and vocal behaviors than at earlier stages.
Starting around 6 months babies also show an influence of the ambient language in their babbling
, i.e., babies’ babbling
sounds different depending on which languages they hear. For example, French learning 9-10 month-olds have been found to produce a bigger proportion of prevoiced
stops
(which exist in French but not English) in their babbling
than English learning infants of the same age. This phenomenon of babbling
being influenced by the language being acquired has been called babbling drift.
Infants now combine different vowel
s and consonant
s into syllable
strings. At this stage, infants also produce various stress
and intonation
patterns. During this transitional period from babbling
to the first word children also produce “protowords”, i.e., invented words that are used consistently to express specific meanings, but that are not real words in the children’s target language. Around 12–14 months of age children produce their first word.
Infants close to one year of age are able to produce rising pitch contour
s in addition to flat, falling, and rising-falling pitch contours.
features not being fully developed until about 12 years of age.
minimal pair
s at a purely phonological level, if the discrimination task is paired with word meaning, the additional cognitive load required by learning the word meanings leaves them unable to spend the extra effort on distinguishing the similar phonology.
s like these already soon after birth, only now are they able to distinguish them if they are presented to them as meaningful words rather than just a sequence of sounds.
Children are also able to detect mispronunciations such as ‘vaby’ for ‘baby’. Recognition has been found to be poorer for mispronounced than for correctly pronounced words. This suggests that infants’ representations of familiar words are phonetically
very precise. This result has also been taken to suggest that infants move from a word-based to a segment
-based phonological system around 18 months of age.
Of course, the reason why children need to learn the sound distinctions of their language is because then they also have to learn the meaning associated with those different sounds. Young children have a remarkable ability to learn meanings for the words they extract from the speech they are exposed to, i.e., to map meaning onto the sounds. Often children already associate a meaning with a new word after only one exposure. This is referred to as “fast mapping
”.
At 20 months of age, when presented with three familiar objects (e.g., a ball, a bottle and a cup) and one unfamiliar object (e.g., an egg piercer), children are able to conclude that in the request “Can I have the zib,” zib must refer to the unfamiliar object, i.e., the egg piercer, even if they have never heard that word before. Children as young as 15 months can complete this task successfully if the experiment is conducted with fewer objects. This task shows that children aged 15 to 20 months can assign meaning to a new word after only a single exposure. Fast mapping
is a necessary ability for children to acquire the number of words they have to learn during the first few years of life: Children acquire an average of nine words per day between 18 months and 6 years of age.
awareness, i.e., they are interested in word play, rhyming, and alliteration
s. Phonological awareness does continue to develop until the first years of school. For example, only about half of the 4- and 5-year olds tested by Liberman et al. (1974) were able to tap out the number of syllable
s in multisyllabic words, but 90% of the 6-year-olds were able to do so.
Most 3-4-year olds are able to break simple consonant
-vowel
-consonant (CVC) syllable
s up into their constituents (onset and rime
). The onset of a syllable
consists of all the consonant
s preceding the syllable’s vowel
, and the rime
is made up of the vowel and all following consonants. For example, the onset in the word ‘dog’ is /d/ and the rime is /og/. Children at 3–4 years of age were able to tell that the nonwords
/fol/ and /fir/ would be liked by a puppet whose favorite sound is /f/. Clearly, these children were able to segment the onset /f/ out of the syllable. 4-year olds are less successful at this task if the onset of the syllable contains a consonant cluster, such as /fr/ or /fl/.
Children under the age of 6 also seem to be unable to break syllables into their individual segments
, aside from separating out the onset. Liberman et al. found that no 4-year-olds and only 17% of 5-year-olds were able to tap out the number of phoneme
s (individual sounds) in a word. 70% of 6-year-olds were able to do so. This suggests that children are aware of syllables as units of speech early on, while they don’t show awareness of individual phoneme
s until school age. One reason why phoneme awareness gets much better once children start school is because learning to read, provides a visual aid as how to break up words into their smaller constituents.
ic patterns in their native language at 7–8 months, they are not able to reliably distinguish compound
words and phrase
s that differ only in stress
placement, such as ‘HOT dog’ vs. ‘hot DOG’ until around 12 years of age. Children in a study by Vogel and Raimy (2002) were asked to show which of two pictures (i.e., a dog or a sausage) was being named. Children younger than 12 years generally preferred the compound reading (i.e., the sausage) to the phrasal reading (the dog). The authors concluded from this that children start out with a lexical bias, i.e., they prefer to interpret phrases like these as single words, and the ability to override this bias develops until late in childhood.
. The lexical items they produce are probably stored as whole words rather than as individual segments
that get put together online when uttering them. This is suggested by the fact that infants at this age may produce the same sounds differently in different words.
processes”, and often resemble processes that are typically common in the adult phonologies
of the world’s languages (cf. reduplication
in adult Jamaican Creole: “yellow yellow” = “very yellow” ). Some common phonological processes are listed below.
- Weak syllable deletion: omission of an unstressed
syllable
in the target word, e.g., [nænæ] for ‘banana’
- Final consonant deletion: omission of the final consonant
in the target word, e.g., [pikʌ] for ‘because’
- Reduplication
: production of two identical syllables based on one of the target word syllables, e.g., [baba] for ‘bottle’
- Consonant harmony
: a target word consonant takes on features of another target word consonant, e.g., [ɡʌk] for ‘duck’
- Consonant cluster reduction: omission of a consonant in a target word cluster, e.g., [kæk] for ‘cracker’
- Velar fronting: a velar
is replaced by a coronal
sound, e.g., [ti] for ‘key’
- Stopping: a fricative
is replaced by a stop
, e.g., [ti] for ‘sea’
- Gliding: a liquid
is replaced by a glide
, e.g., [wæbɪt] for ‘rabbit’
. Their ability to produce complex sound sequences and multisyllabic
words continues to improve throughout middle childhood.
, brain development, and development of neurological structures responsible for vocalization are factors for the development of infants’ vocal productions.
s are smaller, and initially also shaped differently from adults’ vocal tract
s. The infant’s tongue fills the entire mouth, thus reducing the range of movement. As the facial skeleton grows, the range for movement increases, which probably contributes to the increased variety of sounds infants start to produce. Development of muscles and sensory receptors also gives infants more control over sound production.
The limited movement possible by the infant jaw and mouth might be responsible for the typical consonant-vowel (CV) alternation in babbling
and it has even been suggested that the predominance of CV syllables in the languages of the world might evolutionarily have been caused by this limited range of movements of the human vocal organs.
The differences between the vocal tract of infants and adults can be seen in figure 3 (infants) and figure 4 (adults) below.
, which matures earlier than the cortex
. Neurological development of higher brain structures coincides with certain developments in infants’ vocalizations. For example, the onset of cooing at 6 to 8 weeks happens as some areas of the limbic system
begin to function. The limbic system is known to be involved in the expression of emotion, and cooing in infants is associated with a feeling of contentedness. Further development of the limbic system might be responsible for the onset of laughter around 16 weeks of age. The motor cortex
, finally, which develops later than the abovementioned structures may be necessary for canonical babbling
, which start around 6 to 9 months of age.
The acquisition of native language phonology
Phonology
Phonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...
begins in the womb and isn’t completely adult-like until the teenage years. Perceptual abilities (such as being able to segment “thisisacup” into four individual word units) usually precede production and thus aid the development of speech production.
Perception
Children don’t utter their first words until they are about 1 year old, but already at birth they show some utterances in their native language from utterances in languages with different prosodicProsody (linguistics)
In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...
features.
Categorical perception
Infants as young as 1 month perceive some speech sounds as speech categories (they display categorical perception
Categorical perception
Categorical perception is the experience of percept invariances in sensory phenomena that can be varied along a continuum. Multiple views of a face, for example, are mapped onto a common identity, visually distinct objects such as cars are mapped into the same category and distinct speech tokens...
of speech). For example, the sounds /b/ and /p/ differ in the amount of breathiness that follows the opening of the lips. Using a computer generated continuum in breathiness between /b/ and /p/, Eimas et al. (1971) showed that English-learning infants paid more attention to differences near the boundary between /b/ and /p/ than to equal-sized differences within the /b/-category or within the /p/-category. Their measure, monitoring infant sucking-rate, became a major experimental method for studying infant speech perception.
Infants up to 10–12 months can distinguish not only native sounds but also nonnative contrasts. Older children and adults lose the ability to discriminate some nonnative contrasts. Thus, it seems that exposure to one’s native language causes the perceptual system to be restructured. The restructuring reflects the system of contrasts in the native language.
4 months
At four months infants still prefer infant-directed speechBaby talk
Baby talk, also referred to as caretaker speech, infant-directed speech or child-directed speech and informally as "motherese", "parentese", "mommy talk", or "daddy talk" is a nonstandard form of speech used by adults in talking to toddlers and infants.It is usually delivered with a "cooing"...
to adult-directed speech. Whereas 1-month-olds only exhibit this preference if the full speech signal is played to them, 4-month-old infants prefer infant-directed speech even when just the pitch contour
Pitch contour
In linguistics, speech synthesis, and music, the pitch contour of a sound is a function or curve that tracks the perceived pitch of the sound over time....
s are played. This shows that between 1 and 4 months of age, infants improve in tracking the suprasegmental
Prosody (linguistics)
In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...
info in the speech directed at them. By 4 months, finally, infants have learned which features they have to pay attention to at the suprasegmental level.
5 months
Babies prefer to hear their own name to similar sounding words. This indicates that they have associated the meaning “me” with their name.6 months
With increasing exposure to the ambient language, infants learn not to pay attention to sound distinctions that are not meaningful in their native language, e.g., two acoustically different versions of the vowel /i/ that simply differ because of inter-speaker variability. By 6 months of age infants have learned to treat acoustically different sounds that are representations of the same sound categoryCategorical perception
Categorical perception is the experience of percept invariances in sensory phenomena that can be varied along a continuum. Multiple views of a face, for example, are mapped onto a common identity, visually distinct objects such as cars are mapped into the same category and distinct speech tokens...
, such as an /i/ spoken by a male versus a female speaker, as members of the same phonological category /i/.
Statistical learning
Infants are able to extract meaningful distinctions in the language they are exposed to from statistical properties of that language. For example, if English-learning infants are exposed to a prevoiced /d/ to voiceless
Voice (phonetics)
Voice or voicing is a term used in phonetics and phonology to characterize speech sounds, with sounds described as either voiceless or voiced. The term, however, is used to refer to two separate concepts. Voicing can refer to the articulatory process in which the vocal cords vibrate...
unaspirated
Aspiration (phonetics)
In phonetics, aspiration is the strong burst of air that accompanies either the release or, in the case of preaspiration, the closure of some obstruents. To feel or see the difference between aspirated and unaspirated sounds, one can put a hand or a lit candle in front of one's mouth, and say pin ...
/t/ continuum (similar to the /d/ - /t/ distinction in Spanish) with the majority of the tokens occurring near the endpoints of the continuum, i.e., showing extreme prevoicing versus long voice onset times (bimodal distribution
Bimodal distribution
In statistics, a bimodal distribution is a continuous probability distribution with two different modes. These appear as distinct peaks in the probability density function, as shown in Figure 1....
) they are better at discriminating these sounds than infants who are exposed primarily to tokens from the center of the continuum (unimodal distribution).
These results show that at the age of 6 months infants are sensitive to how often certain sounds occur in the language they are exposed to and they can learn which cues are important to pay attention to from these differences in frequency of occurrence. In natural language exposure this means typical sounds in a language (such as prevoiced /d/ in Spanish) occur often and infants can learn them from mere exposure to them in the speech they hear. All of this occurs before infants are aware of the meaning of any of the words they are exposed to, and therefore the phenomenon of statistical learning has been used to argue for the fact that infants can learn sound contrasts without meaning being attached to them.
At 6 months, infants are also able to make use of prosodic
Prosody (linguistics)
In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...
features of the ambient language to break the speech stream they are exposed to into meaningful units, e.g., they are better able to distinguish sounds that occur in stressed
Stress (linguistics)
In linguistics, stress is the relative emphasis that may be given to certain syllables in a word, or to certain words in a phrase or sentence. The term is also used for similar patterns of phonetic prominence inside syllables. The word accent is sometimes also used with this sense.The stress placed...
vs. unstressed syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
s. This means that at 6 months infants have some knowledge of the stress
Stress (linguistics)
In linguistics, stress is the relative emphasis that may be given to certain syllables in a word, or to certain words in a phrase or sentence. The term is also used for similar patterns of phonetic prominence inside syllables. The word accent is sometimes also used with this sense.The stress placed...
patterns in the speech they are exposed and they have learned that these patterns are meaningful.
7 months
At 7.5 months English-learning infants have been shown to be able to segment words from speech that show a strong-weak (i.e., trochaicTrochee
A trochee or choree, choreus, is a metrical foot used in formal poetry consisting of a stressed syllable followed by an unstressed one...
) stress
Stress (linguistics)
In linguistics, stress is the relative emphasis that may be given to certain syllables in a word, or to certain words in a phrase or sentence. The term is also used for similar patterns of phonetic prominence inside syllables. The word accent is sometimes also used with this sense.The stress placed...
pattern, which is the most common stress pattern in the English language, but they were not able to segment out words that follow a weak-strong pattern. In the sequence ‘guitar is’ these infants thus heard ‘taris’ as the word-unit because it follows a strong-weak pattern.
The process that allows infants to use prosodic
Prosody (linguistics)
In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...
cues in speech input to learn about language structure has been termed “prosodic bootstrapping
Bootstrapping
Bootstrapping or booting refers to a group of metaphors that share a common meaning: a self-sustaining process that proceeds without external help....
”.
8 months
While children generally don’t understand the meaning of most single words yet, they understand the meaning of certain phrases they hear a lot, such as “Stop it,” or “Come here.”9 months
Infants can distinguish native from nonnative language input from phoneticPhonetics
Phonetics is a branch of linguistics that comprises the study of the sounds of human speech, or—in the case of sign languages—the equivalent aspects of sign. It is concerned with the physical properties of speech sounds or signs : their physiological production, acoustic properties, auditory...
and phonotactic
Phonotactics
Phonotactics is a branch of phonology that deals with restrictions in a language on the permissible combinations of phonemes...
patterns alone, i.e., without the help of prosodic
Prosody (linguistics)
In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...
cues. They seem to have learned their native language’s phonotactics
Phonotactics
Phonotactics is a branch of phonology that deals with restrictions in a language on the permissible combinations of phonemes...
, i.e., which combinations of sounds are possible in the language.
10-12 months
Infants now can no longer discriminate most nonnative sound contrasts that fall within the same sound categoryCategorical perception
Categorical perception is the experience of percept invariances in sensory phenomena that can be varied along a continuum. Multiple views of a face, for example, are mapped onto a common identity, visually distinct objects such as cars are mapped into the same category and distinct speech tokens...
in their native language. Their perceptual system has been tuned to the contrasts relevant in their native language.
As for word comprehension, Fenson et al. (1994) tested 10-11-month-old children’s comprehension vocabulary size and found a range from 11 words to 154 words. At this age, children normally have not yet begun to speak and thus have no production vocabulary. So clearly, comprehension vocabulary develops before production vocabulary.
Stages of pre-speech vocal development
Even though children do not produce their first words until they are approximately 12 months old, the ability to produce speech sounds starts to develop at a much younger age. Stark (1980) distinguishes five stages of early speech development:0-6 weeks: Reflexive vocalizations
These earliest vocalizations include crying and vegetative sounds such as breathing, sucking or sneezing. For these vegetative sounds, infants’ vocal cords
Vocal folds
The vocal folds, also known commonly as vocal cords, are composed of twin infoldings of mucous membrane stretched horizontally across the larynx...
vibrate and air passes through their vocal apparatus, thus familiarizing infants with processes involved in later speech production.
6-16 weeks: Cooing and laughter
Infants produce cooing sounds when they are content. Cooing is often triggered by social interaction with caregivers and resembles the production of vowels.
16-30 weeks: Vocal play
Infants produce a variety of vowel- and consonant-like sounds that they combine into increasingly longer sequences. The production of vowel
Vowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...
sounds (already in the first 2 months) precedes the production of consonant
Consonant
In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are , pronounced with the lips; , pronounced with the front of the tongue; , pronounced with the back of the tongue; , pronounced in the throat; and ,...
s, with the first back consonants (e.g., [g], [k]) being produced around 2–3 months, and front consonants (e.g., [m], [n], [p]) starting to appear around 6 months of age.
As for pitch contour
Pitch contour
In linguistics, speech synthesis, and music, the pitch contour of a sound is a function or curve that tracks the perceived pitch of the sound over time....
s in early infant utterances, infants between 3 and 9 months of age produce primarily flat, falling and rising-falling contours. Rising pitch contour
Pitch contour
In linguistics, speech synthesis, and music, the pitch contour of a sound is a function or curve that tracks the perceived pitch of the sound over time....
s would require the infants to raise subglottal
Glottis
The glottis is defined as the combination of the vocal folds and the space in between the folds .-Function:...
pressure during the vocalization or to increase vocal fold
Vocal folds
The vocal folds, also known commonly as vocal cords, are composed of twin infoldings of mucous membrane stretched horizontally across the larynx...
length or tension at the end of the vocalization, or both. At 3 to 9 months infants don’t seem to be able to control these movements yet.
6-10 months: Reduplicated babbling (or canonical babbling)
Reduplicated babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
contains consonant-vowel (CV) syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
s that are repeated in reduplicated series of the same consonant
Consonant
In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are , pronounced with the lips; , pronounced with the front of the tongue; , pronounced with the back of the tongue; , pronounced in the throat; and ,...
and vowel
Vowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...
(e.g., [bababa]). At this stage, infants’ productions resemble speech much more closely in timing and vocal behaviors than at earlier stages.
Starting around 6 months babies also show an influence of the ambient language in their babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
, i.e., babies’ babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
sounds different depending on which languages they hear. For example, French learning 9-10 month-olds have been found to produce a bigger proportion of prevoiced
Voice (phonetics)
Voice or voicing is a term used in phonetics and phonology to characterize speech sounds, with sounds described as either voiceless or voiced. The term, however, is used to refer to two separate concepts. Voicing can refer to the articulatory process in which the vocal cords vibrate...
stops
Stop consonant
In phonetics, a plosive, also known as an occlusive or an oral stop, is a stop consonant in which the vocal tract is blocked so that all airflow ceases. The occlusion may be done with the tongue , lips , and &...
(which exist in French but not English) in their babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
than English learning infants of the same age. This phenomenon of babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
being influenced by the language being acquired has been called babbling drift.
10-14 months: Nonreduplicated babbling (or variegated babbling)
Infants now combine different vowel
Vowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...
s and consonant
Consonant
In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are , pronounced with the lips; , pronounced with the front of the tongue; , pronounced with the back of the tongue; , pronounced in the throat; and ,...
s into syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
strings. At this stage, infants also produce various stress
Stress (linguistics)
In linguistics, stress is the relative emphasis that may be given to certain syllables in a word, or to certain words in a phrase or sentence. The term is also used for similar patterns of phonetic prominence inside syllables. The word accent is sometimes also used with this sense.The stress placed...
and intonation
Intonation (linguistics)
In linguistics, intonation is variation of pitch while speaking which is not used to distinguish words. It contrasts with tone, in which pitch variation does distinguish words. Intonation, rhythm, and stress are the three main elements of linguistic prosody...
patterns. During this transitional period from babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
to the first word children also produce “protowords”, i.e., invented words that are used consistently to express specific meanings, but that are not real words in the children’s target language. Around 12–14 months of age children produce their first word.
Infants close to one year of age are able to produce rising pitch contour
Pitch contour
In linguistics, speech synthesis, and music, the pitch contour of a sound is a function or curve that tracks the perceived pitch of the sound over time....
s in addition to flat, falling, and rising-falling pitch contours.
Development once speech sets in (1 year and older)
At the age of 1, children only just begin to speak, and their utterances are not adult-like yet at all. Children’s perceptual abilities are still developing, too. In fact, both production and perception abilities continue to develop well into the school years, with the perception of some prosodicProsody (linguistics)
In linguistics, prosody is the rhythm, stress, and intonation of speech. Prosody may reflect various features of the speaker or the utterance: the emotional state of the speaker; the form of the utterance ; the presence of irony or sarcasm; emphasis, contrast, and focus; or other elements of...
features not being fully developed until about 12 years of age.
14 months
Children are able to distinguish newly learned ‘words’ associated with objects if they are not similar sounding, such as ‘lif’ and ‘neem’. They cannot distinguish similar sounding newly learned words such as ‘bih’ and ‘dih’, however. So, while children at this age are able to distinguish monosyllabicSyllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
minimal pair
Minimal pair
In phonology, minimal pairs are pairs of words or phrases in a particular language, which differ in only one phonological element, such as a phone, phoneme, toneme or chroneme and have distinct meanings...
s at a purely phonological level, if the discrimination task is paired with word meaning, the additional cognitive load required by learning the word meanings leaves them unable to spend the extra effort on distinguishing the similar phonology.
16 months
Children’s comprehension vocabulary size ranges from about 92 to 321 words. The production vocabulary size at this age is typically around 50 words. This shows that comprehension vocabulary grows faster than production vocabulary.18-20 months
At 18–20 months infants can distinguish newly learned ‘words’, even if they are phonologically similar, e.g. ‘bih’ and ‘dih’. While infants are able to distinguish syllableSyllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
s like these already soon after birth, only now are they able to distinguish them if they are presented to them as meaningful words rather than just a sequence of sounds.
Children are also able to detect mispronunciations such as ‘vaby’ for ‘baby’. Recognition has been found to be poorer for mispronounced than for correctly pronounced words. This suggests that infants’ representations of familiar words are phonetically
Phonetics
Phonetics is a branch of linguistics that comprises the study of the sounds of human speech, or—in the case of sign languages—the equivalent aspects of sign. It is concerned with the physical properties of speech sounds or signs : their physiological production, acoustic properties, auditory...
very precise. This result has also been taken to suggest that infants move from a word-based to a segment
Segment (linguistics)
In linguistics , the term segment may be defined as "any discrete unit that can be identified, either physically or auditorily, in the stream of speech."- Classifying speech units :...
-based phonological system around 18 months of age.
Fast-mapping
Of course, the reason why children need to learn the sound distinctions of their language is because then they also have to learn the meaning associated with those different sounds. Young children have a remarkable ability to learn meanings for the words they extract from the speech they are exposed to, i.e., to map meaning onto the sounds. Often children already associate a meaning with a new word after only one exposure. This is referred to as “fast mapping
Fast mapping
In cognitive psychology, fast mapping is a hypothesized mental process whereby a new concept can be learned based only on a single exposure to a given unit of information...
”.
At 20 months of age, when presented with three familiar objects (e.g., a ball, a bottle and a cup) and one unfamiliar object (e.g., an egg piercer), children are able to conclude that in the request “Can I have the zib,” zib must refer to the unfamiliar object, i.e., the egg piercer, even if they have never heard that word before. Children as young as 15 months can complete this task successfully if the experiment is conducted with fewer objects. This task shows that children aged 15 to 20 months can assign meaning to a new word after only a single exposure. Fast mapping
Fast mapping
In cognitive psychology, fast mapping is a hypothesized mental process whereby a new concept can be learned based only on a single exposure to a given unit of information...
is a necessary ability for children to acquire the number of words they have to learn during the first few years of life: Children acquire an average of nine words per day between 18 months and 6 years of age.
2–6 years
At 2 years, infants show first signs of phonologicalPhonology
Phonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...
awareness, i.e., they are interested in word play, rhyming, and alliteration
Alliteration
In language, alliteration refers to the repetition of a particular sound in the first syllables of Three or more words or phrases. Alliteration has historically developed largely through poetry, in which it more narrowly refers to the repetition of a consonant in any syllables that, according to...
s. Phonological awareness does continue to develop until the first years of school. For example, only about half of the 4- and 5-year olds tested by Liberman et al. (1974) were able to tap out the number of syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
s in multisyllabic words, but 90% of the 6-year-olds were able to do so.
Most 3-4-year olds are able to break simple consonant
Consonant
In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are , pronounced with the lips; , pronounced with the front of the tongue; , pronounced with the back of the tongue; , pronounced in the throat; and ,...
-vowel
Vowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...
-consonant (CVC) syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
s up into their constituents (onset and rime
Syllable rime
In the study of phonology in linguistics, the rime or rhyme of a syllable consists of a nucleus and an optional coda. It is the part of the syllable used in poetic rhyme, and the part that is lengthened or stressed when a person elongates or stresses a word in speech.The rime is usually the...
). The onset of a syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
consists of all the consonant
Consonant
In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are , pronounced with the lips; , pronounced with the front of the tongue; , pronounced with the back of the tongue; , pronounced in the throat; and ,...
s preceding the syllable’s vowel
Vowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...
, and the rime
Syllable rime
In the study of phonology in linguistics, the rime or rhyme of a syllable consists of a nucleus and an optional coda. It is the part of the syllable used in poetic rhyme, and the part that is lengthened or stressed when a person elongates or stresses a word in speech.The rime is usually the...
is made up of the vowel and all following consonants. For example, the onset in the word ‘dog’ is /d/ and the rime is /og/. Children at 3–4 years of age were able to tell that the nonwords
Pseudoword
A pseudoword is a unit of speech or text that appears to be an actual word in a certain language , while in fact it is not part of the lexicon. Within linguistics, a pseudoword is defined specifically as respecting the phonotactic restrictions of a language...
/fol/ and /fir/ would be liked by a puppet whose favorite sound is /f/. Clearly, these children were able to segment the onset /f/ out of the syllable. 4-year olds are less successful at this task if the onset of the syllable contains a consonant cluster, such as /fr/ or /fl/.
Children under the age of 6 also seem to be unable to break syllables into their individual segments
Segment (linguistics)
In linguistics , the term segment may be defined as "any discrete unit that can be identified, either physically or auditorily, in the stream of speech."- Classifying speech units :...
, aside from separating out the onset. Liberman et al. found that no 4-year-olds and only 17% of 5-year-olds were able to tap out the number of phoneme
Phoneme
In a language or dialect, a phoneme is the smallest segmental unit of sound employed to form meaningful contrasts between utterances....
s (individual sounds) in a word. 70% of 6-year-olds were able to do so. This suggests that children are aware of syllables as units of speech early on, while they don’t show awareness of individual phoneme
Phoneme
In a language or dialect, a phoneme is the smallest segmental unit of sound employed to form meaningful contrasts between utterances....
s until school age. One reason why phoneme awareness gets much better once children start school is because learning to read, provides a visual aid as how to break up words into their smaller constituents.
12 years
Although children perceive rhythmRhythm
Rhythm may be generally defined as a "movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions." This general meaning of regular recurrence or pattern in time may be applied to a wide variety of cyclical natural phenomena having a periodicity or...
ic patterns in their native language at 7–8 months, they are not able to reliably distinguish compound
Compound (linguistics)
In linguistics, a compound is a lexeme that consists of more than one stem. Compounding or composition is the word formation that creates compound lexemes...
words and phrase
Phrase
In everyday speech, a phrase may refer to any group of words. In linguistics, a phrase is a group of words which form a constituent and so function as a single unit in the syntax of a sentence. A phrase is lower on the grammatical hierarchy than a clause....
s that differ only in stress
Stress (linguistics)
In linguistics, stress is the relative emphasis that may be given to certain syllables in a word, or to certain words in a phrase or sentence. The term is also used for similar patterns of phonetic prominence inside syllables. The word accent is sometimes also used with this sense.The stress placed...
placement, such as ‘HOT dog’ vs. ‘hot DOG’ until around 12 years of age. Children in a study by Vogel and Raimy (2002) were asked to show which of two pictures (i.e., a dog or a sausage) was being named. Children younger than 12 years generally preferred the compound reading (i.e., the sausage) to the phrasal reading (the dog). The authors concluded from this that children start out with a lexical bias, i.e., they prefer to interpret phrases like these as single words, and the ability to override this bias develops until late in childhood.
12-14 months
Infants usually produce their first word around 12 –14 months of age. First words are simple in structure and contain the same sounds that were used in late babblingBabbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
. The lexical items they produce are probably stored as whole words rather than as individual segments
Segment (linguistics)
In linguistics , the term segment may be defined as "any discrete unit that can be identified, either physically or auditorily, in the stream of speech."- Classifying speech units :...
that get put together online when uttering them. This is suggested by the fact that infants at this age may produce the same sounds differently in different words.
16 months
Children’s production vocabulary size at this age is typically around 50 words, although there is great variation in vocabulary size among children in the same age group, with a range between 0 and 160 words for the majority of children.18 months
Children’s productions become more consistent around the age of 18 months. When their words differ from adult forms, these differences are more systematic than before. These systematic transformations are referred to as “phonologicalPhonology
Phonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...
processes”, and often resemble processes that are typically common in the adult phonologies
Phonology
Phonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...
of the world’s languages (cf. reduplication
Reduplication
Reduplication in linguistics is a morphological process in which the root or stem of a word is repeated exactly or with a slight change....
in adult Jamaican Creole: “yellow yellow” = “very yellow” ). Some common phonological processes are listed below.
Whole word processes (until age 3 or 4)
- Weak syllable deletion: omission of an unstressed
Stress (linguistics)
In linguistics, stress is the relative emphasis that may be given to certain syllables in a word, or to certain words in a phrase or sentence. The term is also used for similar patterns of phonetic prominence inside syllables. The word accent is sometimes also used with this sense.The stress placed...
syllable
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
in the target word, e.g., [nænæ] for ‘banana’
- Final consonant deletion: omission of the final consonant
Consonant
In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are , pronounced with the lips; , pronounced with the front of the tongue; , pronounced with the back of the tongue; , pronounced in the throat; and ,...
in the target word, e.g., [pikʌ] for ‘because’
- Reduplication
Reduplication
Reduplication in linguistics is a morphological process in which the root or stem of a word is repeated exactly or with a slight change....
: production of two identical syllables based on one of the target word syllables, e.g., [baba] for ‘bottle’
- Consonant harmony
Consonant harmony
Consonant harmony is a type of "long-distance" phonological assimilation akin to the similar assimilatory process involving vowels, i.e. vowel harmony.-Examples:...
: a target word consonant takes on features of another target word consonant, e.g., [ɡʌk] for ‘duck’
- Consonant cluster reduction: omission of a consonant in a target word cluster, e.g., [kæk] for ‘cracker’
Segment substitution processes (into the early school years)
- Velar fronting: a velar
Velar consonant
Velars are consonants articulated with the back part of the tongue against the soft palate, the back part of the roof of the mouth, known also as the velum)....
is replaced by a coronal
Coronal consonant
Coronal consonants are consonants articulated with the flexible front part of the tongue. Only the coronal consonants can be divided into apical , laminal , domed , or subapical , as well as a few rarer orientations, because only the front of the tongue has such...
sound, e.g., [ti] for ‘key’
- Stopping: a fricative
Fricative consonant
Fricatives are consonants produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate, in the case of German , the final consonant of Bach; or...
is replaced by a stop
Stop consonant
In phonetics, a plosive, also known as an occlusive or an oral stop, is a stop consonant in which the vocal tract is blocked so that all airflow ceases. The occlusion may be done with the tongue , lips , and &...
, e.g., [ti] for ‘sea’
- Gliding: a liquid
Liquid consonant
In phonetics, liquids or liquid consonants are a class of consonants consisting of lateral consonants together with rhotics.-Description:...
is replaced by a glide
Semivowel
In phonetics and phonology, a semivowel is a sound, such as English or , that is phonetically similar to a vowel sound but functions as the syllable boundary rather than as the nucleus of a syllable.-Classification:...
, e.g., [wæbɪt] for ‘rabbit’
2 years
The size of the production vocabulary ranges from about 50 to 550 words at the age of 2 years. Influences on the rate of word learning, and thus on the wide range of vocabulary sizes of children of the same age, include the amount of speech children are exposed to by their caregivers as well as differences in how rich the vocabulary in the speech a child hears is. Children also seem to build up their vocabulary faster if the speech they hear is related to their focus of attention more often. This would be the case if a caregiver talks about a ball the child is currently looking at.4 years
A study by Gathercole and Baddeley (1989) showed the importance of sound for early word meaning. They tested the phonological memory of 4- and 5-year-old children, i.e., how well these children were able to remember a sequence of unfamiliar sounds. They found that children with better phonological memory also had larger vocabularies at both ages. Moreover, phonological memory at age 4 predicted the children’s vocabulary at age 5, even with earlier vocabulary and nonverbal intelligence factored out.7 years
Children produce mostly adult-like segmentsSegment (linguistics)
In linguistics , the term segment may be defined as "any discrete unit that can be identified, either physically or auditorily, in the stream of speech."- Classifying speech units :...
. Their ability to produce complex sound sequences and multisyllabic
Syllable
A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...
words continues to improve throughout middle childhood.
Biological foundations of infants’ speech development
The developmental changes in infants’ vocalizations over the first year of life are influenced by physical developments during that time. Physical growth of the vocal tractVocal tract
The vocal tract is the cavity in human beings and in animals where sound that is produced at the sound source is filtered....
, brain development, and development of neurological structures responsible for vocalization are factors for the development of infants’ vocal productions.
Infants’ vocal tract
Infants vocal tractVocal tract
The vocal tract is the cavity in human beings and in animals where sound that is produced at the sound source is filtered....
s are smaller, and initially also shaped differently from adults’ vocal tract
Vocal tract
The vocal tract is the cavity in human beings and in animals where sound that is produced at the sound source is filtered....
s. The infant’s tongue fills the entire mouth, thus reducing the range of movement. As the facial skeleton grows, the range for movement increases, which probably contributes to the increased variety of sounds infants start to produce. Development of muscles and sensory receptors also gives infants more control over sound production.
The limited movement possible by the infant jaw and mouth might be responsible for the typical consonant-vowel (CV) alternation in babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
and it has even been suggested that the predominance of CV syllables in the languages of the world might evolutionarily have been caused by this limited range of movements of the human vocal organs.
The differences between the vocal tract of infants and adults can be seen in figure 3 (infants) and figure 4 (adults) below.
The nervous system
Crying and vegetative sounds are controlled by the brain stemBrain stem
In vertebrate anatomy the brainstem is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves...
, which matures earlier than the cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
. Neurological development of higher brain structures coincides with certain developments in infants’ vocalizations. For example, the onset of cooing at 6 to 8 weeks happens as some areas of the limbic system
Limbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...
begin to function. The limbic system is known to be involved in the expression of emotion, and cooing in infants is associated with a feeling of contentedness. Further development of the limbic system might be responsible for the onset of laughter around 16 weeks of age. The motor cortex
Motor cortex
Motor cortex is a term that describes regions of the cerebral cortex involved in the planning, control, and execution of voluntary motor functions.-Anatomy of the motor cortex :The motor cortex can be divided into four main parts:...
, finally, which develops later than the abovementioned structures may be necessary for canonical babbling
Babbling
Babbling is a stage in child development and a state in language acquisition, during which an infant appears to be experimenting with uttering sounds of language, but not yet producing any recognizable words...
, which start around 6 to 9 months of age.