Michael Halliday

Michael Alexander Kirkwood Halliday (often M.A.K. Halliday; 13 April 1925 – 15 April 2018) was an English-born linguist. He developed the internationally influential "systemic functional linguistic" model of language. His grammatical works go by the name of "systemic functional grammar" ("SFG").
Halliday described himself as a "generalist", meaning that he has tried "to look at language from every possible vantage point", and has described his work as "wander[ing] the highways and byways of language".
Halliday died in Sydney of natural causes on 15 April 2018 at the age of 93.