ATR Vowel Harmony: new patterns and diagnostics
This paper presents a large-scale typological study of over 500 Nilo-Saharan and Niger-Congo vowel inventories, both with and without ATR harmony. The survey reveals: i) ATR contrasts in high vowels correlate with a strong likelihood of ATR harmony; ii) the vowel system /i e ɛ a ɔ o u/ (termed 1IU in Casali 2008) does not correlate well with ATR harmony. In Nilo-Saharan, such systems do not show ATR harmony, and in Niger-Congo, the majority of such systems also do not have harmony. The survey results are interpreted in terms of perceptual distance, driven by inventory contrast. High vowel ATR contrasts are perceptually more difficult than mid contrasts and activate harmony. In languages that lack mid vowel contrasts, [+ATR] harmony derives allophonic [e o] from /ɛ ɔ/. In languages that lack high vowel contrasts, mid vowel contrasts do not present enough of a perceptual difficulty to reliably activate harmony. If harmony is present, it tends to operate only between mid vowels and does not generate allophonic high vowels.