Michael Alexander Kirkwood Halliday was a British linguist who developed the internationally influential systemic functional linguistics (SFL) model of language. His grammatical descriptions go by the name of systemic functional grammar. Halliday described language as a semiotic system, "not in the sense of a system of signs, but a systemic resource for meaning". For Halliday, language was a "meaning potential"; by extension, he defined linguistics as the study of "how people exchange meanings...