The purpose of this study is two-fold. One is to identify how place of articulation and manner of articulation affect coarticulation and the other is to identify how following vowel affects coarticulation by child''s developmental paths in Korean stops and affricates.
F2 onset frequency and F2 vowel frequency were measured in the subjects of 60 children aged 2 years and 6 months to 6 years and 5 months on the CVC syllables made up of stops, affricates and vowels /a, i, u, e/, and then the linear regression analysis was used to obtain the slopes of locus equations. Through the slopes, the extent of coarticulation was quantified, and for the comparison by the phonemes and the age groups, repeated-measure ANOVA and one-way ANOVA were conducted respectively.
The findings from the first purpose show that in all age groups coarticulation of stops and affricates by place of articulation has the order of velar sounds followed by bilabial sounds, alveolar sounds, and palatal sounds, among which velar sounds are found to show the continuous increase in terms of extent of coarticulation in proportion to the subjects'' age.
Stops coarticulation by manner of articulation show the order of aspirated > glottalized > lenis from the age 5 up, among which aspirated sounds were found to show increase in terms of extent of coarticulation with the age getting older. Affricates coarticulation show the order of aspirated > lenis > glottalized from the age 4 up.
The findings from the second research purpose show that the vowel /e/ known as neutral position among following vowels affects coarticulation the most. Among the corner vowels /a, i, u/, /i/ was found to show the greatest in terms of extent of coarticulation, while /a/ and /u/ were not discernible. The vowel /i/ was found to show stable coarticulation as the age gets older, while the vowel /a/ showed the greatest variability by the age.
Through this study, it was confirmed that extent of coarticulation in the Korean language varies by place of articulation, manner of articulation and following vowels, and it was also found that the effect of coarticulation gets bigger as children get older from the age 2 to 6.