Sooner or later, as schools move to implement the new Common Core and other forthcoming standards, almost every teacher in the United States will face the challenge of how to support students from homes where English is not the dominant language in meeting subject-matter academic expectations that require increasingly demanding uses of language and literacy in English. In this article, the author reviews research that provides potential insights on how "mainstream" teachers might be prepared for responding to this challenge, both in preservice teacher preparation programs and throughout their careers. The author argues that efforts to prepare teachers for working with English learners (ELs) to engage with increasing language and literacy expectations across the curriculum requires development of "pedagogical language knowledge" (Galguera, 2011)--not to "teach English" in the way that most mainstream teachers may initially conceive of (and resist) the notion, but rather to purposefully enact opportunities for the development of language and literacy in and through teaching the core curricular content, understandings, and activities that teachers are responsible for (and, hopefully, excited about) teaching in the first place. The author reviews recent literature that presents various approaches to what this knowledge might entail and how teacher preparation and development initiatives might go about fostering it. The author concludes by proposing that, in an age of increasing linguistic demands associated with new academic expectations, building teachers' understanding of language as "action" (van Lier & Walqui, 2012) could serve as the foundation for preparing them to engage--and support--ELs in both challenging and meaningful academic tasks. (Contains 1 table and 6 notes.)