Articulatory correlates of phonemic and coarticulatory nasalization

• Published in: The Journal of the Acoustical Society of America Vol. 142; no. 4; p. 2552
• Main Authors: Barlaz, Marissa, Liang, Zhi-Pei, Sutton, Brad
• Format: Journal Article
• Language: English
• Published: 01-10-2017
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.5014329

Phonological theory distinguishes nasal and oral vowel counterparts by velopharyngeal port opening, neglecting other phonetic differences between phonemic and coarticulatory nasalization. Recent articulatory work provides evidence of oropharyngeal distinctions, in addition to velic lowering. This study (12 Brazilian Portuguese speakers) uses real-time MRI to investigate oropharyngeal differences between oral, phonemically nasal, and phonetically nasalized vowels /a, i, u/. Tissue boundaries in midsagittal vocal tract images were automatically detected to reveal each vowel repetition’s aperture function. Principal Components Analysis determined vocal tract regions responsible for the greatest variance in the data. Time-dynamic analyses of vocal tract area in these regions used smoothing spline ANOVA. Results show the tongue body and/or hyperpharynx as the most important articulators. For /a/, nasal vowels demonstrate wider hyperpharyngeal and narrower tongue body regions compared to oral vowels. For /u/, oral vowels show wider hyperpharyngeal and narrower tongue body regions. For /i/, nasal vowels demonstrate wider tongue body and narrower hyperpharyngeal regions. Nasalized vowels manifest apertures intermediate between oral and nasal vowels for /a/ and /u/, and similar to oral vowels for /i/. Results are largely in line with expected acoustic effects of nasalization, and demonstrate that phonetic differences exist between phonemic and coarticulatory nasalization.