Neutral Vowels in Lokaa Harmony

This paper discusses the neutral vowels in Lokaa harmony, [i, u, {schwa}, a]. By neutral I mean a segment which has no harmonic counterpart. Such segments are either transparent or opaque. Lokaa harmony is important in three crucial respects. First, while it is rare to find a language which has both transparent and opaque vowels in its harmony, Lokaa does. The high vowels [i, u] are transparent to harmony; the low vowel [a] is opaque, and the status of the mid vowel schwa is indeterminate. Secondly, though Lokaa has an eight-vowel inventory the vowels [a] and schwa have not 're-paired' (Bakovic 2000, 2003). They do not alternate, as we find for example in the neighboring language Igede (Bergman 1971, Armstrong 1983), or in Wolof (Ka 1994) which has an identical vowel system. Thirdly, the historic ATR contrast found in Benue-Congo high vowels (Stewart 1971, Williamson 1973) shows up when high vowel stems take mid-vowel prefixes, though the high vowels can only be [+ATR] on the surface. That is, the ATR merger of high vowels in Lokaa is not complete