Ticuna

Ticuna, or Duüxügu, is the language of the Ticuna people of the upper Amazon, spoken along the Solimões and its tributaries for roughly a thousand kilometres from Cajacuma in Peru east past the Jutaí in Brazil. It is generally treated as an isolate: its only demonstrated relative, Yuri, is extinct, and recent work ties the pair to Carabayo, spoken by an uncontacted group in Colombia. Phonologically it is exceptional even by Amazonian standards, with six vowel qualities that may be nasalised, creaky-voiced or both, and one of the largest tone inventories in the world — five tone levels plus four falling contours in the standard Peruvian description, counted as 8 to 12 phonemic tones depending on dialect and analyst. It is polysynthetic, splits nouns into free and bound (obligatorily possessed) classes, and assigns every noun masculine, feminine or neuter gender that need not match Spanish or Portuguese. With 51,978 speakers recorded in Brazil's 2022 census alone it is the most widely spoken Indigenous language in that country and one of the few Amazonian languages Ethnologue still rates as stable.