informant

1. (linguistics) A native speaker who acts as a linguistic reference for a language being studied. The informant demonstrates native pronunciation, provides grammaticality judgments regarding linguistic well-formedness, and may also explain cultural references and other important contextual information.Examples: "The only material the linguist has to begin with are the informant's grammatical utterances in the target language pronounced arbitrarily in a natural or assigned communicative situation or stimulated artificially by the investigator."; "The informant learns his language by formal training and, more importantly, by constant exposure to its use. He cannot repeat to the linguist what he has never seen or heard."