Vocalic context as a condition for nasal coda emergence: Aerodynamic evidence

Nasal coda emergence (NCE) (sometimes referred to as 'restoration') is the process by which a nasal vowel develops an excrescent nasal coda which may or may not have been present in an earlier form of the spoken language. NCE is operative in the Carioca (Rio de Janeiro) dialect of Brazilian Portuguese (CBP), an Ibero-Romance language with five phonemically nasal vowels. The output of NCE (in this language) is usually a velar nasal. It has been suggested that the process may be a function of tongue position (Hajek 1991: 262). To test the null hypothesis that NCE does not correlate with vowel height or anteriority, aerodynamic (nasal and oral flow) signals were obtained from three speakers of CBP. The speakers uttered words ending in nasal vowels while wearing a circumferentially-vented pneumotach split-flow air mask. For comparative purposes, parallel data were gathered from a Hindi and a French speaker as well. The maximum nasal percentage of total flow and the maximum real nasal flow (in ml/s) were measured for each token, averaged across vowels and, in the case of CBP, across speakers. For CBP, the null hypothesis is rejected, lending support to the alternative: vowel height and posteriority indeed condition the emergence of NCE. This suggests a role for the lowered velum and/or raised tongue body in the development of coda obstruents on nasal vowels.