The issue of vowel height harmony – relatively rare in the
languages – is one that most serious theories of phonology have addressed
at one time or another, particularly as concerns its realisation in Bantu
(e.g. Clements 1991, Archangeli & Pulleyblank 1994, Beckman 1997).
is quite well known, the majority of an estimated 500 Bantu languages
exhibit some variant of a progressive harmony process by which vowels
lower when preceded by an appropriate (lower) trigger. (Ki)-Yaka, a
Western Bantu language spoken in ex-Zaire, designated as H.31 by
Guthrie (1967–71), has a height harmony system which has been analysed
as having a similar left-to-right lowering process. In this paper I argue
against the general analysis given for Yaka, showing that this language
differs in a major way from the rest of Bantu. The goals of the paper are
threefold. First, I present a comprehensive treatment of the unusual vowel
harmony system in (ki-)Yaka. Second, I introduce the notion of the
‘prosodic trough’ (τ), a domain which is needed in order
important phonological generalisations in Yaka and in Bantu in general.
Finally, I show the relevance of the Yaka facts for the study of positional
prominence in phonology. A (partial) analysis is offered within optimality-
theoretic terms, particularly as developed by McCarthy & Prince (1995).
Although superficially resembling the vowel height harmony found in
most Bantu languages, the Yaka system will be shown to differ from these
latter in major ways. The paper is organised as follows. In §2 I establish
the general nature of the Yaka harmony system, reanalysing previous
accounts in terms of ‘plateauing’. In §3 I turn to the
‘imbrication’, which introduces a second motivation for vowel
the avoidance of the sequence [wi]. A third source of vowel harmony
presented in §4, which also introduces the notion of the ‘prosodic
The study ends with a brief conclusion in §5 and an appendix that
discusses outstanding problems.