Phonetics and phonology of nasality in Ecuadorian Siona

This study describes the nasal system in Ecuadorian Siona, an endangered Western Tukanoan language spoken in the Ecuadorian province of Sucumbíos, using the Earbuds Method to analyze nasal events acoustically. This method provides a visual representation of the timing and duration of velum gestures through intensity (dB) and amplitude (Pa) fluctuations in the nasal and oral cavities. The studied events include nasal spreading (nasal harmony), triggers, targets, blockers, and transparent segments. Meanwhile, differences between nasal phonemes and nasal allophones are also identified along with the effects of morpheme boundaries during nasal spreading events. Results reveal that, unlike many other Tukanoan languages, /m/ and /n/ function as individual phonemes independent of their oral counterparts (/p̰/ & /t̰/). In addition, nasal harmony was identified as predominantly rightward spreading apart from syllable-delimited leftward spreading to vocoid segments. Moreover, suffixes responsible for blocking nasal spreading appear to be reminiscent of oral suffixes in Eastern Tukanoan languages. Finally, more blockers were identified in Ecuadorian Siona than in most Eastern Tukanoan languages.