Vowel harmony: The behaviour of the vowel /a/ in [+ATR] environment Constance Kutsch Lojenga, Leiden University / SIL The aim of this paper is to document the behaviour of the vowel /a/ when found in a [+ATR] environment in three Bantu languages spoken in the north-east of the Democratic Republic of Congo. The three Bantu languages concerned are Budu, Bila, and Lika, all classified as Bantu D. All three languages have a nine-vowel system with ATR harmony. The vowel /a/ does not have a [+ATR] counterpart in the underlying structure. For each of the three languages, I look at vowel harmony first of all from a static perspective, investigating V1 – V2 cooccurrences and cooccurrence restrictions within roots. It is found that, in general, the vowel /a/ is transparent in that it can cooccur both with [–ATR] and [+ATR] vowels within roots. Following that, I study the dynamic aspect of vowel harmony, in which I look at behaviour of the vowel /a/ occurring in noun-class prefixes and verb-final suffixes when attached to a [+ATR] root. In all three languages, the vowel /o/ may occur as [+ATR] counterpart of /a/; however, the details differ from one language to the other. Finally, I consider some cases of idiosyncratic behaviour in numeral prefixes, and a case of [–ATR] dominance in Lika, in which a final root vowel /o/ is changed to /a/.