Following a widely accepted definition by Valdes (2000), a heritage language is a language that is acquired by individuals raised in homes where the dominant language of the region, such as English in the United States, is not spoken or not exclusively spoken. A heritage language is typically acquired before a dominant language but is not completely acquired because of the individual's switch to that dominant language. This incompletely acquired version of a home language, then, is what is known as a heritage language. (Polinsky, M. & Kagan, O., 2007)

By an early age, heritage speakers will be to some degree bilingual in the dominant language and the heritage language(s). Research has identified tremendous variation in the proficiencies of heritage speakers. However, the key point, under this definition of heritage language, is that the learning trajectories of heritage speakers — particularly those speakers who eventually make a formal study of a heritage language — differ markedly from the trajectories of second-language learners with little or no previous exposure to a target language.

The definition of a heritage speaker in general and for specific languages continues to be debated. The debate is of particular significance in such languages as Chinese, Arabic, and languages of India and the Philippines, where speakers of multiple languages or dialects are seen as heritage speakers of a single standard language taught for geographic, cultural or other reasons (Mandarin Chinese, Classical Arabic, Hindi, or Tagalog, respectively).

There is also a broad definition of heritage language that emphasizes possible links between cultural heritage and linguistic heritage. A definition by Fishman (2001:81) stresses a "particular family relevance" of a language, and Van Deusen-Scholl (2003:222) defines those who "have been raised with a strong cultural connection to a particular language through family interaction" as language learners (not speakers) "with a heritage motivation."

Under these broader conceptions, a heritage language may be equivalent to a second language in terms of linguistic competence, and its acquisition may begin in the classroom, in adulthood.

Heritage language speakers can usually be considered bilingual to some degree, and the heritage language is usually the person’s first language

First language

A first language is the language a person has learned from birth or within the critical period, or that a person speaks the best and so is often the basis for sociolinguistic identity...

. However, it is important to note differences in the ways that heritage learners use the heritage language and the dominant language. Heritage learners can be characterized by a fluent command of the dominant language and are comfortable using it in formal settings, due to their exposure to the language through formal education. Their command of the heritage language, however, can vary much more widely. Some heritage learners may lose some fluency in the first language after beginning formal education in the dominant language. Others may speak the heritage language consistently at home and with family, but receive minimal to no formal training in the heritage language and thus may struggle with literacy skills or using it in broader settings outside of the home. As bilingualism and biculturalism become increasingly valuable, however, educators have begun to look at how to help heritage learners develop and maintain greater fluency in their heritage language.

See also

• First language
  First language
  A first language is the language a person has learned from birth or within the critical period, or that a person speaks the best and so is often the basis for sociolinguistic identity...
  
  
• Second language
  Second language
  A second language or L2 is any language learned after the first language or mother tongue. Some languages, often called auxiliary languages, are used primarily as second languages or lingua francas ....
  
  
• Bilingualism
• Children of deaf adult(s)
  Child of deaf adult
  A child of a deaf adult, often known by the acronym "CODA", is a person who was raised by a deaf parent or guardian. Many CODAs identify with both deaf and hearing cultures...
  
  
• Language acquisition
  Language acquisition
  Language acquisition is the process by which humans acquire the capacity to perceive, produce and use words to understand and communicate. This capacity involves the picking up of diverse capacities including syntax, phonetics, and an extensive vocabulary. This language might be vocal as with...