Munduruku is a Tupi language spoken by 10,000 people in the Tapajós River basin in north central Brazil, of which most of the women and children are monolingual.
Those who live in the villages of the Tapajós River valley speak only Munduruku, even in the presence of non-indigenous people.
"[2] The syllable in Munduruku is made up of an obligatory vocalic nucleus and one of four phonemic accents (three of pitch and one of laryngealization).
The onset in this language may be any one of the 16 consonant phonemes which contrast as to the manner and point of articulation: (1) voiceless stops /p, t, k, tʃ, k, ʔ/; (2) Voiced stops /b, dʒ/; (3) Fricatives /s, ʃ, h/, (4) nasals /m, n, ŋ/, (5) Sonorants /w, y, r/ The only segment not allowed in the coda is /tʃ/.
There is also a phonetic contrast between /i, u/ as vowel nuclei and /y, w/ as codas, the former being distinctly vocalic and the latter consonantal.