In this chapter, we outline the unique advantages of systemic functional linguistics (SFL) to describe spoken and written discourse in texts and provide a strong foundation for English language learners to produce their own stretches of spoken and written discourse. We also provide practical applications of SFL theory through example activities based on a genre-based approach to language teaching using a teaching-learning cycle, which builds on Vygotsky’s concept of the Zone of Proximal Development and Bruner’s notion of scaffolding. SFL is a comprehensive and at the same time fully appliable linguistics. Learning a second language involves making meanings about the world, making meanings to interact with others in the world, and creating cohesive and coherent texts, all at the same time. Making choices from the language system is fundamental. By combining a social semiotic view of language with socially oriented theories of language learning involving semiotic mediation through scaffolding, second language teachers can be explicit about the linguistic properties of texts in context and offer the right kinds of support and guidance through cycles of language learning and teaching.