Gabriel Wyner

Trained as an opera singer, which meant learning to sing convincingly in German, Italian and French, and built a language method out of the shortcuts he needed.

Fluent Forever puts pronunciation first, on the argument that if you cannot hear a distinction you will never store the word, then uses spaced repetition with images rather than translations so the new language never routes through English.

Wyner is not a linguist and leans on cognitive research he did not conduct. The pronunciation-first sequencing is the part most teachers concede he is right about.