At one point or another, every theory of speech production has to contend with the transition from discrete phonological units or categories to "continuously varying phonetic dimension". Similarly every theory of speech perception has to contend with the inverse transition - i.e. from the phonetic continuum to the discreteness of the phonological level. The use of a certain phonetic dimension in a given language may or may not reflect a corresponding contrast in the phonology of that language. Vowel nasalisation for example, is a phonetic phenomenon which does not reflect a phonological contrast in, say English, although this phonetic phenomenon is often present to some extent wherever a derived level non-nasal vowel occurs between nasal consonants. The present paper analyses the main acoustic realisations of nasal vowels.
