We have not found a single instance in which a nasalized low vowel is lower than the corresponding oral vowel, whereas the following instances indicate clearly that nasalization has a raising effect on low vowels.
Bhat (1975: 30ff.) explains away the counterexamples through other conditioning factors that co-occur with nasalization that cause lowering, such as closed syllables, in which nasalization is not strong enough to block.
1. Other linguists (Pope 1966, Lightner 1970, Posner 1971, Chen 1973c, Ohala 1974) have argued the opposite, i.e. the general tendency in language is for the nasalized vowels to move towards a lower tongue height. (cf. #1288)2. Bhat (1975: 27) clarifies his statement by arguing the effect of nasalization (or a neighboring nasal) on a vowel is either the neutralization of the height distinction or the raising of the vowel height.
1. Other linguists (Pope 1966, Lightner 1970, Posner 1971, Chen 1973c, Ohala 1974) have argued the opposite, i.e. the general tendency in language is for the nasalized vowels to move towards a lower tongue height. (cf. #1288)2. Bhat (1975: 27) clarifies his statement by arguing the effect of nasalization (or a neighboring nasal) on a vowel is either the neutralization of the height distinction or the raising of the vowel height.