발화 조절에 따른 한국어 모음의 음성적 특징과 오류 양상 분석

Acoustic characteristics of Korean vowels according to speech accommodation: clear speech vs. conversational speech

The present study was to investigate the extent to which clear speech is an effective intelligibility enhancement strategy for non-native speakers of Korean. Ten Chinese advanced learners were participated in speech production test. Acoustic differences between clear speech (CL) and conversational speech (CON) of Korean monophthongs were measured on durations, f1 and f2 values, vowel quadrilateral spaces, and the vowel identification test was evaluated. The results were as follows: (1) the paired t-test on durations showed a statistical significance between CL and CON, which means the durations of CL were longer than those of CON. (2) The two-way repeated measure ANOVA was conducted that examined the effect of vowels and utterance levels on vowel quadrilateral area (Hz²). The vowel spaces of CL were even larger than those of CON across all seven vowels. (3) the vowel identification scores of individual tokens demonstrated the similar error rates for both CL and CON. Although it is important to understand speech accommodation effect for speech clarity, these results suggest that the expanded temporal and spectral properties may not guarantee the accuracy of listeners’ identification of vowels. Other factors (e.g., learners’ anxiety) affecting second language acquisition should be discussed for further research.