The acoustic correlates of stress and tone in Chácobo (Pano): A production study

This paper investigates the acoustic correlates of word initial prominence and tone in Chácobo, a southern Pano language of the northern Bolivian Amazon. This paper reports the results of a production study with five speakers producing trisyllabic words with a word final high tone. It tests a claim found in the literature that there is an additional word-initial prominence in such forms and determines its acoustic correlates compared with high tone. This study used trisyllabic forms in morphophonological contexts where these forms would appear with a final high tone. In such forms, high tone and word-initial prominence do not overlap (e.g., "panaß̞í" "asaí"). The paper takes into account five acoustic correlates across the three syllables of these words: F1, F2, F0, duration, intensity. The paper finds that the initial syllable in these words shows a statistically significant increase in intensity. There is significant speaker variation with respect to whether duration is a correlation of initial stress and the results do not provide clear evidence that initial stress is marked with duration. The final high-tone marked syllables are distinguished based on an increase in F0 and secondarily with vowel duration. Whether pitch is also a correlate of stress requires future research. The paper interprets these results as suggesting that Chácobo is a language in which tone and stress co-exist. The study thus provides instrumental evidence for a phenomenon suggested to occur in some Pano languages. The limitations of this study, including the fact the results have more than one interpretation in light of current discussions concerning stress and tone, are also discussed.