Conditional relevance is the property of an interactional act whose production is, to some degree, expectable given a previous utterance. In other words, it is the property of an interactional act which a previous act sequentially implicates. The second pair parts of adjacency pairs (see below) are made conditionally relevant by the first pair parts of such pairs of actions. (Note that not all utterances or actions produced in the presence of others is an interactional act. For our purposes, such acts are only those we would define as signals given--intentionally produced actions which the producer intends to be understood as intentionally produced.)

Sequential implication is the effect of any interactional act that makes another act expectable. In other words, it is the effect of an interactional act that makes another act conditionally relevant.

An adjacency pair is pair of acts (usually but not necessarily utterances) produced in an interpersonal interaction. The first act (labled a first pair part or "fpp"), is produced by one interactant, the second (labled a second pair part or "spp") is produced by a different interactant than the first. These pairs are characterized by the fact that the fpp makes the spp conditionally relevant, and the spp can be only one or two things, given the nature of the fpp. Thus, for instance, leave-taking exchanges are adjacency pairs because the fpp of such an exchange--e.g., person A saying "goodbye," seems to require that a similar action (e.g., a "good-bye" from person B) follow. Any failure to produce the expected action (i.e., any "silence" by person B--the one expected to produce an spp) gets read as a refusal to perform the expected action or as a joke. Remember that not all utterances are parts of an adjacency pair (often times we have many more options for following an utterance than the one or two required by adjacency pairs), nor are they all parts of insertion sequences.

An insertion sequence is any set of actions exchanged between two or more interactants that comes between the first and second pair parts of an adjacency pair. They are always interpreted in light of the adjacency pair in which they are enclosed. Note that while initiations of conversational repairs are often initiations of insertion sequences, they aren’t necessarily so, as might be the case when one mistakenly seeks repair for an utterance that wasn’t really meant for you.