The distribution of the feature [high] in Shona verbs
is a
prototypical example of positional neutralisation accompanied by vowel
harmony. In
languages which exhibit positional neutralisation of vowel contrasts, one
or more vowels (generally, the most marked members of the vowel
inventory) may occur distinctively in only a small subset of the structural
positions available in the language. Outside of these positions, the marked
vowels may surface only if they harmonise with a similar vowel in the
privileged position. For example, the mid vowels e and o
in Shona verbs
are contrastive only in root-initial syllables. These vowels may appear
in
subsequent syllables only when preceded by a mid vowel in root-initial
position. A string of height-harmonic Shona vowels is therefore firmly
anchored in the root-initial syllable, as shown in (1):