The Forgotten Mid-Vowels: Reconstructing the History of the Proto-Pano Vowel System

This study critically reexamines the Proto-Pano phonological inventory, challenging the prevailing view that it contained only four oral vowels. Through a comparative analysis of 22 contemporary Pano languages, we reconstruct a Proto-Pano system that includes two additional mid vowels, thus proposing a six-vowel inventory. This finding diverges from all previous Pano reconstructions, which lacked a careful consideration of the historically significant differences between mid vowels in Northern Pano languages, and Kakataibo and Kashararí. We argue that mid vowels in these languages represent both conservative and innovative traits within the family, questioning the assumption that all Pano mid vowels are innovative. Our analysis highlights the roles of merger and split processes in shaping Pano phonological diversity, suggesting that a six-vowel reconstruction better accounts for the comparative data and that Pano mid vowels have origins that are diverse and divergent. This revised framework provides new insights into the historical evolution and internal classification of the Pano language family.