A linguist is a person who studies linguistics, a branch of study of language.

Such a person is engaged in the scientific study or application of both the theoretical and the practical aspects of language.

Theoretical linguistics include grammar, syntax, semantics, origin of words and meanings and phonetics etc.

Applied linguistics includes practical utilization of the knowledge of a language, such as an interpreter, translator, a speech therapist, or a language teacher or professor.

Though the words written and spoken often intertwine, a linguist typically focuses more on the spoken word than the written word.