The Cori language is a minor Plateau language

Plateau languages

-Characteristics:Only some of the languages have nominal classes, as the Bantu languages have, where in others these have eroded. The large numbers of consonants in many languages is due to the erosion of noun-class prefixes....

 spoken in a single village in Kaduna

Kaduna

Kaduna is the state capital of Kaduna State in north-central Nigeria. The city, located on the Kaduna River, is a trade center and a major transportation hub for the surrounding agricultural areas with its rail and road junction. The population of Kaduna is at 760,084 as of the 2006 Nigerian census...

 State in Nigeria

Nigeria

Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

.

Cori is known for having six distinct levels of tone

Tone (linguistics)

Tone is the use of pitch in language to distinguish lexical or grammatical meaning—that is, to distinguish or inflect words. All verbal languages use pitch to express emotional and other paralinguistic information, and to convey emphasis, contrast, and other such features in what is called...

, too many to transcribe using the International Phonetic Alphabet

International Phonetic Alphabet

The International Phonetic Alphabet "The acronym 'IPA' strictly refers [...] to the 'International Phonetic Association'. But it is now such a common practice to use the acronym also to refer to the alphabet itself that resistance seems pedantic...

, which allows five. However, there are only three underlying tones: 1 , 4 , and 6 , which are all that need to be written for literacy. Most cases of Tone 2 are a result of tone sandhi

Tone sandhi

Tone sandhi is a feature of tonal languages in which the tones assigned to individual words vary based on the pronunciation of the words that surround them in a phrase or sentence. It is a type of sandhi, or fusional change, from the Sanskrit word for "joining".-Languages with tone sandhi:Not all...

, with 4 becoming 2 before 1. Tones 3 and 5 can be analyzed as contour tones, with underlying /1͡6/ realized as [3] and /2͡6/ realized as [5].

In order to transcribe the surface tones without numerals (which are ambiguous), an extra diacritic is needed, as is common for four-level languages in Central America:

1 [ő]

2 [ó]

3 [o̍]

4 [ō]

5 [ò]

6 [ȍ]