This presentation will include discussion of both challenges and strategies in meeting the 2007 MLA Report’s calls for change in lower-division FL courses and, in particular, in relation to TA professional development. A pedagogy of multiliteracies (Gee, 1990; Kern, 2000; New London Group, 1996; Swaffar & Arens, 2005) is posited as an appropriate framework for anchoring TA professional development and several concepts from Vygotskian cultural-historical psychology (e.g., everyday and scientific concepts, appropriation, dialogic mediation, assisted performance) are foregrounded as key elements of professional development activities. Examples will be shared from several empirical studies of TA conceptual development (Allen, 2011; Allen & Dupuy, 2011; Dupuy & Allen, in press) as analyzed in both early in-service and later FL pedagogy seminars.