Bororo (Borôro), also known as Boe, is the sole surviving language of a small family believed to be part of the Macro-Gê languages. It is spoken by the Bororo, hunters and gatherers in the central Mato Grosso region of Brazil.
Phonology
Bororo has a mid-sized phonemic inventory of seven vowels and fifteen consonants. Orthographic representations, when they differ from IPA, are shown in angle brackets (all from Nonato 2008, based on Americanist transcription).
Vowels
The vowel system of Bororo is somewhat cross-linguistically unusual in that it distinguishes roundedness only in its back vowels (although Crowell (1979) analyzes unrounded “back” vowels as central).
The mid vowels /e ɤ o/ alternate with the open-mid (or "lax") vowels [ɛ ʌ ɔ] in apparent free variation.
The unrounded back vowels /ɯ ɤ/ become central [ɨ ɘ] word-finally. Furthermore, [ɘ] (i.e. word-final /ɤ/) is not distinguished from, and often surfaces as, front [ɛ]. As a result, /ɤ/ and /e/ are at least partially merged word-finally.
Diphthongs and long vowels
Bororo has a rich inventory of twelve diphthongs:
All pure vowels can also occur long, i.e. as /iː eː ɯː ɤː uː oː aː/. In contrast to other languages with phonemic vowel length, however, these are quite rare, and there seems to be no reason to distinguish long vowels from same-vowel sequences. This is evidenced by the mandatory lengthening of monosyllables, where the vowel of a monosyllable is repeated to form a long vowel: for example, /ba/ "village" becomes /baa̯/ [baː].
Consonants
Unusually for a South American language, Bororo has no phonemic fricatives.
The velar stop /k/ becomes aspirated [kʰ] before nonback vowels /a e i/; the labiovelar approximant /w/ becomes labiodental in the same environment. Plain and labialized velar stops / g kʷ ɡʷ/ merge as labialized [kʷ ɡʷ] before rounded vowels /u o/. The voiced velar stop /g/ lenites to fricative between vowels.
Syllable structure and stress
The canonical syllable structure in Bororo is : that is, a mandatory vowel nucleus (or diphthong), optionally preceded by a single onset consonant. Aside from unmodified loanwords from Portuguese (which are quite common, and becoming more so), Bororo syllables never have onset consonant clusters or codas.
Stress in Bororo occurs generally (again with the exception of unmodified Portuguese loanwords) on the penultimate mora. Since diphthongs contain two morae, this means that a diphthong in either penultimate or final position will generally be stressed: [ˈbai̯ɡa] "bow", [kaˈnao̯] "pimple, scale". Before compounding, however, diphthongs are reanalyzed as a monomoraic syllable, and stress is assigned again to the penultimate syllable of the whole compound: [keˈrakae̯] "finger", from /kera/ "hand" and /kae̯/ "digit".
Morphophonology
Bororo has a process of stem-initial mutation. When a stem (whether a noun, verb, or preposition) beginning in a consonant takes on a prefix itself containing a consonant, the stem-initial consonant is voiced; for example, "to go" becomes "I go" with the first person singular (prefix i-) but "we go" in first person plural inclusive (prefix pa-). In addition, /b/ becomes /w/ and /dʒ/ becomes /j/ when following a prefix, regardless of whether the latter has a consonant or not: "for" becomes "for me". Stems beginning with /d g m n r j w/ do not undergo any change. This process is part of a wider harmony restriction in Bororo, rare among the world's languages: no word (excluding clitics and compounds) may contain more than one voiceless obstruent.
Meanwhile, a stem beginning in a vowel requires the insertion of a "thematic" consonant to attach a prefix. The consonant used varies both by the prefix and the stem-initial vowel: the first-person singular, first-person plural exclusive, and third-person plural prefixes insert the thematic consonant -t-/-d- before stems beginning in a- or o-, while all other combinations (i.e. other personal prefixes or stem-initial i-; no native stems begin in e- or u-) insert -k-/-g-. For example, whereas ore "children" becomes i-t-ore "my children", "steal" becomes "I steal". A few irregular stems which would be expected to take -t-/-d- instead take -n-: oika "anxiety" becomes "my anxiety", rather than or similar. Finally, since vowel-initial stems never take a third-person singular prefix, no thematic vowel is inserted. This process is summarized in the table below.