An explanation of Bantu vowel height harmony in terms of a Pre-Bantu nasalized vowel lowering

Abstract

The vowel height harmony displayed by certain verbal extensions in Bantu languages has often been compared with the Advanced Tongue Root (ATR) harmonies of non-Bantu languages such as Akan and Igbo, but it has never been shown to be cognate with them. It is here shown to be cognate instead with a nasalization harmony which is found in some languages of the Tano (Greenberg's Akan-Guang) group and which has been reconstructed in Proto-Tano. The sound correspondences across Potou-Tano and Bantu provide strong evidence that the nasalization harmony goes back to Proto-Potou-Tano-Bantu, the latest common ancestor of the Potou-Tano and Bantu languages, and also that Proto-Potou-Tano-Bantu I becomes e~ at some stage of Pre-Bantu. This nasalized vowel lowering, in applying to sequences such as I-I, introduces a complication into the nasalization harmony, which now incorporates a secondary vowel height harmony. Both harmonies survive in Proto-Bantu and in present-day UMbundu R.II in the extreme west. In the non-northwestern Bantu languages other than UMbundu, however vowel nasalization is lost and only the vowel height harmony survives intact; a trace of the lost vowel nasalization harmony does survive in many of UMbundu's neighbours in the nasal consonant harmony displayed by the verbal extensions in question, but in the eastern Bantu languages there appears to be no trace of it whatsoever.