  Chomsky regards language as a system of grammatical rules “tacitly known” by a speaker. Linguistics, which Chomsky treats as a branch of cognitive psychology, studies the grammatical competence of individual speakers. It should not posit a mysterious and unscientific “communal language” shared by speakers, but should instead focus upon “idiolects.” Thus, language has no special ties to social interaction or communication. Specifically, it has no special ties to convention. Stephen Laurence (1996) and Stephen Schiffer (2006) develop theories of the “actual language” relation informed by a broadly Chomskian perspective. The basic idea behind both accounts is that a linguistic item as used by some speaker is associated with certain semantic properties just in case the association between the linguistic item and the semantic property figures in the psychological processes through which the speaker assigns meanings (or truth-conditions) to sentences.