Cognitive linguistics seeks to account for “a speaker’s knowledge of the full range of linguistic conventions” (Langacker 1987; also Goldberg 2006). It is surprising therefore that little attention has been paid in cognitive linguistics to the linguistic conventions called “discourse markers” (Schiffrin 1987) or “pragmatic markers” (Fraser 2009, et passim). Pragmatic markers include signals of attention to social relationships (well, please), beliefs (I think, in fact), and discourse management (after all, anyway). Members of the third subtype are metatextual connectors of discourse segments (“discourse markers” in Fraser’s taxonomy). I argue that because pragmatic markers (PMs) in general play a major role in negotiating meaning, they are an important part of speakers’ knowledge of language. PMs are well-known not to have truth-conditional meaning, and not to be syntactically integrated with the host clause. However, they have conventional pragmatic meanings (Hansen 2012, Finkbeiner 2019). In English they are typically associated with a slot preceding the core clause and sometimes medial and final slots. I exemplify my recent research on the historical development in English of metatextual discourse markers with a diachronic construction grammar perspective on by the way (Traugott 2020). Focus will be on the importance of routinized, replicated contexts in change (Croft 2001, Bybee 2010).