The labiodental flap/ⱱ/ is marginal, only occurring in two native Buwal words. The labial-velar plosives are also marginal; in particular, /kp/ only occurs in one word, the ideophonekpaŋ.
Buwal has the vowels /əa/, which can occur in high, middle, or low tone. Each vowel has a variety of phonetic realizations. /ə/ can occur as [iuɪʏʊ], and /a/ can occur as [eoɛœɐɔ]. The schwa can be analyzed as a solely epenthetic vowel. These vowels occur as roundedallophones when adjacent to a labialized consonant, and as front vowels when the word is palatalized.
Palatalization in Buwal occurs across an entire word, and also affects the affricate consonants /tsdzⁿdz/, which surface as [tʃdʒⁿdʒ] in a palatalized word. As a result, all of the vowels within a single word are either front or back, producing vowel harmony. An example of this contrast is between [mɐ̄ⁿdʊ́wɐ́n] 'rat' (underlyingly /māⁿdwán/), which is non-palatalized, and [mɛ̀vɛ̄ɗvɛ̄ɗɛ̄ŋ] (underlyingly /màvāɗvāɗāŋ/) 'turtle', which is palatalized. This process does not affect loanwords, e.g. [nɛ̀bɐ̄m] 'oil' (from Fulfuldenebbam) or [lɛ̀kʷól] 'school' (from Frenchl'école). Some loanwords have been modified to accommodate Buwal phonology, e.g. [sɐ́j] 'tea', from Fulfulde sha'i.[2]