An adjacency pair is composed of two utterances by two speakers, one after the other. The speaking of the first utterance (the first-pair part, or the first turn) provokes a responding utterance (the second-pair part, or the second turn). Adjacency pairs are a component of pragmatic variation in the study of linguistics, and are considered primarily to be evident in the "interactional" function of pragmatics.
A sequence of two utterances by two individuals is considered an adjacency pair. The first speaker's utterance (the initial part) triggers a response from the second speaker (the subsequent part). Adjacency pairs are a key aspect of linguistic variation in the study of language, particularly within the realm of pragmatics.