Downstep exceptions in Ibibio

Abstract

Downdrift and downstep are processes which may cause lowering of high tone syllables. Downdrift is intonational, occurring at phrasal or utterance level, while downstep is a phonological process which acts from one tone-bearing unit to the next such that H tones lower successively. The relationship between these larger tonal lowering processes and individual tone units is complicated, however, by processes which may raise or preserve original high tone pitches. Ibibio, a Niger-Congo language spoken in southeastern Nigeria, is a terraced tone language with contrastive H and L tones. H tones in Ibibio experience automatic and non-automatic downstep, lowering both in sequences of high tones and around intervening lows. This study aims to determine those factors which counteract or overrule the downstep process. Average pitch readings were taken of entire syllables and compared with readings of other syllables within the same word. The main finding of this study is that while single words show acoustically measurable downtrends, they also show non-lowering and even raising of high tones, specifically in HHL contexts. This complicates how downtrends act across tone-bearing syllables, and may indicate that a high tone is raised in order to increase contrast with a following low.