According to Hajek’s (2005) world-wide survey, contrastive nasal vowels are found only in about a quarter of the world’s languages, with a heavy areal concentration in equatorial South America and West Africa. Among the APiCS languages, 34 are reported to have some nasal vowels:
|Present in a prominent way||14|
|Present in a limited way||9|
|Present only as minor allophones||11|
|No nasal vowels exist||42|
Thus, it is not surprising that almost all of the languages with nasal vowels in APiCS are spoken in the Atlantic region. There seems to be a clear substrate effect here, with nasalization of vowels in African languages influencing the creoles (Boretzky 1983: 53-56, Parkvall 2000: 30-31). APiCS has nasal vowels also in South Asia and in the Indian Ocean, which again fits with Hajek’s observations, as he finds a local concentration of languages with vowel nasalization in South Asia.
But the lexifier languages, too, have a strong influence on the distribution of nasal vowels. French and Portuguese have nasal vowel phonemes, so nasal vowels are particularly prominent in languages with these lexical bases.
Nasal vowels are said to be present in a prominent way if there are nasal vowels as major allophones in at least three different heights (e.g. ĩ, ɛ̃, ã; see Chapter 121 on vowel height). Of the 14 languages in this category, eight are based on Portuguese, which has three heights of nasal vowels. Four are English-based languages, where the nasal vowels are clearly secondary, deriving from sequences of vowel + syllable-final nasal, for example:
Nasal vowels are present in a limited way if there are some nasal vowels as major allophones, but at most in two vowel heights. This is the pattern of French (which only has [ã], [ɛ̃], [ɔ̃]), and almost all French-based creoles are represented in this value. (Tayo in New Caledonia is the only French-based creole that lacks nasal vowels, evidently because the Austronesian substrates lack them.)
Another 11 languages have nasal vowels only as minor allophones. Since vowels are always to some extent phonetically nasalized in front of nasal consonants, more languages could probably be categorized in this way.