Sir Karl Popper (/kɑ:l pɒpə/ 1902-1994) was an Austrian-born British philosopher of science.
He rejected inductivism in the scientific method in favour of empirical falsification. The scientific method is obviously relevant to linguistics.
Popper moved to New Zealand in 1937 to escape Nazism as he had a Jewish background, and then the UK in 1946.
He may have worked as a teacher and also, as a native German speaker, at some point learnt English as a second language.