Objectives: In this study, we investigated the impact of chronic nasal obstruction on articulation of the Turkish voiceless plosive (stop) consonants and examined the effect of the nose- and mouth-breathing on the articulatory characteristics of the specific speech sounds.
Patients and methods: Twenty-one controls with nose-breathing and 20 patients with mouth breathing were included in this study. The nasal obstruction history of the patients was 10 to 22 years. In the mouth-breather group, intranasal pathologies except septal deviation and turbinate hypertrophy were excluded. The nose-breather subjects without nasal pathologies served as the control group. The subjects graded nasal obstruction through visual analog scale (VAS) from 0 to 10. The minimal cross-sectional area (MCA) and minimal cross-sectional volume (MCV) at the level of septal tubercle and the head of inferior turbinate were established to be 1 and 2 by acoustic rhinometry. Minimal cross-sectional volume was defined as the volume below the curve. The syllables [pa], [ta], [ka] uttered by the subjects were recorded for the spectrographic analysis. Voice onset time (VOT) was measured on wide-band spectrogram.
Results: The VOT value of /p/ was found lower and the VOT values for /t/ and /k/ were found higher in mouth-breathers compared to nose-breathers, while the difference was not statistically significant. The right and left-sided VAS values of the nasal obstruction group were significantly higher compared to controls (p=0.001). The right and left-sided MCA1, MCA2, MCV1 and MCV2 were found statistically different between the two groups.
Conclusion: It was concluded that the articulation features of plosive consonants were not significantly affected by nasal obstruction.