The previous chapter reviewed the historical development of the educational situation in British Columbia. This chapter will review our response to that situation, and the thinking behind it. The main points of this chapter can be summarised as follows. Change is needed in assumptions and practices concerned with language as a m edium of learning as educational systems become m ore multilingual and multicultural. This, rather than second lan guage acquisition, is the central issue. Since it takes a considerable time to learn a second language for academic purposes, to learn to use it adequately as a m edium of learning content and culture means that ESL students must learn language and subject m atter and culture at the same time. To m eet this goal, explicit and systematic integration of language teaching and content teach ing is required, a development which could bring educational benefits to students in general. Language as a m edium of learning requires a functional theory of language and discourse. Systemic functional linguistics provides one. Within the perspective of systemics, the ‘Knowledge Framework’ pro vides a theoretical basis for aspects of language as a m edium of learning. It provides links between second language development and first language development, and between language development and educational develop m ent generally. The Knowledge Framework takes a functional view of lan guage as discourse in the context of social practice. It supports the functional analysis of discourse and a language socialisation perspective. Two ways it can be applied are: with a focus on knowledge structures, or with a focus on activities and tasks (see the detailed discussion of task in Chapter 11).