Spontaneous nasalization

Abstract

Distinctively nasal vowels usually develop from earlier sequences of vowel + nasal consonant. There are exceptions, however, called instances of “spontaneous nasalization,” where an earlier nasal is lacking, e.g., Hindi [sɑ̃:p] “snake” from Sanskrit sarpa; English [hɑ̃vəd] “Harvard.” Curiously, most such spontaneously nasalized vowels have obstruents with high airflow next to them, e.g., voiceless fricatives. We tested a hypothesis that vowels flanking such consonants might sound nasalized without being nasilized if produced with a slightly open glottis via assimilation to the greater-than-normal glottal opening required by the high airflow segments. The spectral effects of open glottis duplicate those of nasilization: increased formant bandwidth, etc. Physiological recordings of syllables such as [bis], [bɑs], by two speakers each of American English and Mexican Spanish showed no true nasalization on the vowels but did show appreciable glottal opening just before the [s]. Using digital techniques, the last complete period of these vowels before the [s] was iterated into a steady-state vowel 400 ms long and presented to listeners who, as predicted, judged them to sound significantly more “nasalized” than control stimuli. [Supported by NSF.]