Local consonant–vowel (C–V) interaction is attested
in many languages,
both as a phonetic and as a phonological process. There can be a clear
developmental relationship between the two, with phonologisation of
phonetic interaction occurring quite commonly (Hyman 1976, Ohala
1981). Thus, a common (historical) context for nasal vowels is an adjacent
nasal consonant. When consonants trigger non-local effects (i.e. when the
domain of the consonantal feature extends beyond adjacent segments),
typically both vowels and consonants are targeted. For example, in
consonant-induced nasal or emphasis harmony all segments in the
harmony domain usually take the consonantal feature. If some segments
are neutral, targets still include both consonants and vowels.