This paper outlines the general influence of Halliday's (1994, 2014) systemic functional linguistics on TESOL curriculum. Halliday's explanation of language as a social semiotic and language learning as learning to mean has been applied internationally in genre and textbased teaching. The concept of register in systemic functional linguistics describes linguistic variation of texts for the expression of different meanings. SFL studies document teachers' explicit instruction in the lexicogrammatical construction of text types linked to function and social context. The explicitness informs students' decision-making for formulation of meanings in different text types. Reference is made to SFL applied in teacher education. There is mention of the relevance of SFL to Australia's concern with literacy standards in education.