In introducing this special issue of "Bilingualism: Language and Cognition," we feel it is critical to clarify what we understand "linguistic convergence" to mean in the context of bilingualism, since "convergence" is a technical term more readily associated with the field of language contact than with the field of bilingualism (for recent discussions of the role of convergence in contact see Thomason and Kaufman, 1988; Thomason, 2001; Myers-Scotton, 2002; Clyne, 2003; Winford, 2003). Within the language contact literature, the term invites a variety of uses. Some researchers adopt a definition of convergence that requires that all languages in a contact situation change, sometimes to the extent that the source of a given linguistic feature cannot be determined (see April McMahon's commentary in this issue). For others, convergence may be more broadly defined to also apply to situations in which one language has undergone structural incursions of various sorts from contact with another.