In Karitiana, word-medial nasals occurring between oral vowels may surface as circum-oralized, post-oralized, or completely oralized consonants. For example, the word for ‘thing’ may surface as [ki.'dnda], [ki~.'nda], or [ki.'da]. Interestingly, this surface variation of Karitiana nasals is due to the temporal indeterminacy of nasal gestures in the language, i.e. the duration of velic aperture varies significantly across tokens. This sort of temporal indeterminacy has not been documented for any language in the literature, and similar surface variation of nasal forms in other languages has been shown to result from asynchrony between velic oscillation and oral occlusion. The author provides acoustic data that illustrate clearly the temporal indeterminacy in question. These data were recently recorded and analyzed in the field, and demonstrate conclusively that velic aperture duration is far from constant in the language. This fact contravenes expectations based on the literature, and it remains to be seen if and how it will be handled by contemporary phonological models.