The language with 84 consonants died with one man in 1992

Ubykh, a Northwest Caucasian language once spoken near the Black Sea, packed in 84 distinct consonants but only about three vowel sounds, one of the most lopsided sound inventories ever recorded. Its last fully fluent speaker, Tevfik Esenç, spent decades helping French linguist Georges Dumézil document the language before he died in 1992, taking it with him.

— Georges Dumézil, La Langue des Oubykhs — Paris, 1931 (foundational linguistic monograph on Ubykh)