A nasal vowel is a vowel that is produced with a lowering of the soft palate (or velum) so that the air flow escapes through the nose and the mouth simultaneously, as in the French vowel /ɑ̃/ () or Amoy [ɛ̃]. By contrast, oral vowels are produced without nasalization.
Nasalized vowels are vowels influenced by nearby sounds. For instance, the [æ] of the word hand in English is affected by the following nasal consonant. In most languages, vowels adjacent to nasal consonants are produced partially or fully with a lowered velum in a natural process of assimilation and are therefore technically nasal, but few speakers would notice. That is the case in English: vowels preceding nasal consonants are nasalized, but there is no phonemic distinction between nasal and oral vowels, and all vowels are considered phonemically oral.
