This paper investigates variation in the use of conventional expressions as a pragmatic resource for realizing speech acts (the actional level of Barron & Schneider 2009). From the perspective of pragmatics, studying variation in the use of conventional expressions shows that some speech acts and contexts promote greater use of conventional expressions; additionally, some conventions are used by more speakers in a community than others, but the reasons require investigation. From the perspective of better understanding concepts such as conventional expressions, investigating variation in welldefined contexts such as those specified by the empirical study of pragmatics shows that basic units like conventional expression must be carefully defined, and that concepts such as ‘community-wide use’ or ‘social agreement’ must be quantified in some way to be meaningful.