Within the linguistic study of endangered languages, sociolinguists distinguish between different speaker types based on the type of competence they have acquired of the endangered language. Often when a community is gradually shifting away from an endangered language to a majority language, not all speakers acquire full linguistic competence; instead, speakers have varying degrees and types of competence depending on their exposure to the minority language in their upbringing. The relevance of speaker types in cases of language shift was first noted by Nancy Dorian, who coined the term semi-speaker to refer to those speakers of Sutherland Gaelic who were predominantly English-speaking and whose Gaelic competence was limited and showed considerable influence from English. Later studies added additional speaker types such as rememberers (who remember some words and phrases but have little or no grammatical competence and do not actively speak the language), and passive speakers (who have nearly full comprehension competence but do not actively speak the language). In the context of language revitalization, new speakers who have learned the endangered language as a second language are sometimes distinguished.
In contexts of language acquisition and language teaching studies, there is sometimes a distinction between native speakers and second language speakers, depending on whether the language was learned as a language of primary socialisation or after having fully acquired a first language. In contexts of multilingualism a bilingual speaker may also be described as a heritage speaker (although a heritage language actually refers to a language whose speakers have moved from the original area where the language was spoken: e.g. Welsh is a heritage language in Patagonia, but not in Wales) if they have not been as fully exposed to one of their languages, leading to a diminished degree of confidence in themselves as speakers, and sometimes also limited competence in one of their languages.