The Acoustic Characteristics of Nasal Consonants in Turkish

Nasal consonants are speech sounds that involve the nasopharyngeal and nasal cavities in the vocal tract during articulation. Acoustically, they are like vowels, but one can differentiate them from vowels by their lower energy. In Turkish, there are two nasal consonants that act as a phoneme: the bilabial consonant /m/ and the alveolar (or dental) consonant /n/. “The palatal n” (/ŋ/), which occurs in some Anatolian dialects, is not a separate phoneme; rather, it is an allophone of the consonant /n/. This study aims to establish the acoustic properties of Turkish nasal consonants, develop a method to demonstrate the presence of “the palatal n”, and establish a reference source for evaluating speech problems related nasal consonants. We prepared a list of 28 single or two-word terms for this study. Ten volunteers (five males and five females) each read the list, and we recorded them. Using the Praat program, we measured the acoustic features of the nasal consonants, including fundamental frequencies, formant and antiformant frequencies, spectral slope parameters, durations and amplitudes, and formant transitions on adjacent vowels. The median values for frequencies of the first, second, and third formants of the [m] consonant measured as 262, 1255, and 2418 Hz for the men, and 279, 1425, and 2444 Hz for the women; the values for [n] consonants were 270, 1546, and 2507 Hz for the men, and 295, 1690, and 2794 Hz for the women. In the narrow band amplitude histogram used to show the antiformant, we observed that the bands with the lowest amplitudes fell between 1500-2000 Hz for [m] and [n]. In addition, it was determined that the most important acoustic parameter indicating “the palatal n” is formant movements on neighboring vowels. The inconsistencies reported in the literature on acoustic properties of nasal consonants, especially related formant values, was also observed in our study. We then decided that it would be appropriate to use a single vowel neighborhood instead of different vowel neighborhoods and further to increase the number of subjects to overcome this problem, particularly in clinical phonetic studies.

Keywords

acoustic phonetics, phonetics, nasal consonants, nasality, nasalization