An Acoustic Study of Vowel Development in a Child Acquiring Taiwan Southern Min

• Main Authors: Yun-wei Lee, 李韵葳
• Other Authors: Jane Tsay
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/03039754722385744303

碩士 === 國立中正大學 === 語言所 === 96 === This thesis is an acoustic analysis of vowel development of a child acquiring Taiwan Southern Min. There are six non-nasal monophthongs /i/, /e/, /a/, /u/, /ɔ/, and /ə/ in this language. The corpus data of the child at 15, 18, 21, and 24 months were analyzed. F1 and F2 of vowels in intelligible words were measured using Praat (Boersma & Weenink, 2006). Changes in F1 and F2 values over the four periods were reported and plotted on the vowel space to examine the development. The caretakers'' speech was also analyzed for comparison. The results showed that firstly, child vowels had higher F1 and F2 than the adult ones. Larger distance between F1 and F2 was also found in child vowels. Mean F1 at 15 months was 960 Hz and mean F2 was 2011 Hz compared to 705 Hz and 1853 Hz, respectively for the adult. Consequently, the distribution of the vowels in child speech was gathered in the central and low area in vowel space compared to the distribution of the adult''s vowels. Young children''s smaller vocal tract results in producing higher formant frequencies. Second, productions of vowels had high variation in early stages, possibly due to the immature control of the articulators. This results in the remarkable overlaps of different target vowels at 15 months, the first period of our investigation. Centralization of vowel productions of each vowel category should be found in vowel space with the more mature control of the articulators as the child grew up. The two high vowels /i/ and /u/ were the first vowels produced with less variation. The steady production of these two vowels started at 18 months, the second period, and beyond. Steady productions of the other vowels did not occurred until 21 months, the third period. Finally, vowel space started expanding with the front-back dimension at 18 months. The expansion of high-low dimension did not started until the age of 21 months. Child vowel space resembled the adult one at the age of 24 months. This study shows that F1 and F2 values were overall higher than the adult ones during the second year of life, and vowel space expansion was remarkable in this period.