ABSTRACT
This paper aimed to study what the influences of orthodontic treatment of pronunciation are. We compared the duration and the acoustic wave patterns of Korean consonants pronounced by a control group with those of a patient who had his four premolars extracted and had been given orthodontic treatment The results were as follows : 1. Compared to the control group, the treatment group had a longer duration time of consonant pronunciation for all consonants but "s " and "th" in CV(consonant-vowel) pairs. Especially in the case of "dz", "phih" for CV-pairs, and "d" in VCV(vowel-consonant-vowel) clusters, the duration of consonant sound showed a sharp contrast between the control group and the treatment group. 2. There were clear differences in the acoustic wave patterns of "ts", "phih" and "ch", all of which were in VCV-clusters. The acoustic wave pattern of "ts", when pronounced by the treatment group, was stronger than the control group's. This phenomenon was most remarkable in the transitive section where the "ts" sound flowed into the following vowel. When a preceding vowel shifted to the consonant "phih", the attack property of the appeared clearly in the acoustic waves of the t,reament group, while in the control group the starting point of consonart was indistinctive. Consonant duration for the treatment group was longer, and the appearance of a zero crossing point in the acoustic wave was more frequent. In the case of "ch", the treatment group produced a strong acoustic wave, and the property of aspiration was obvious in it 3. When the treatment group pronounced "d" and "dz" in CV-pairs, the acoustic-wave was similar to that of aspirated "th" and "ch". 4. The aspirated "th" and "ch" pronounced by the treatment group showed the stronger airstream and acoustic wave form.