This study is a comprehensive acoustic description and analysis of the six vowels /i e a u o ɔ/ in the Towet dialect of the Papuan language Nungon ⟨yuw⟩ of northeastern Papua New Guinea. Vowel tokens were extracted from a corpus of audio speech recordings created for general language documentation and grammatical description. To assess the phonetic correlates of a claimed phonological vowel length distinction, vowel duration was measured. Multi-point acoustic analyses enabled investigation of mean vowel F1, F2, and F3; vowel trajectories, and coarticulation effects. The three Nungon back vowels were of particular interest, as they contribute to an asymmetrical, back vowel-heavy array, and /o/ had previously been described as having an especially low F2. The authors found that duration of phonologically long and short vowels differed significantly. Mean vowel formant measurements confirmed that the six phonological vowels form six distinct acoustic groupings; trajectories show slightly more formant movement in some vowels than was previously known. Adjacent nasal consonants exerted significant effects on vowel formant measurements. The authors show that an uncontrolled, general documentation corpus for an under-described language can be mined for acoustic analysis, but coarticulation effects should be taken into account.