말은 언어적 기호를 조음 및 음향학적으로 산출하는 것으로 언어를 들을 수 있게 표현하는 것이다. 음소(phoneme)란 언어의 기본적인 단위로써 언어의 소리체계로 묘사되는 것을 말한다. 음소는 2개의 중요한 모음과 자음으로 분류된다. 그리고 그들은 공명의 음향학적인 패턴과 관련이 있으며, 단음절어의 변별 능력에도 중요한 영향을 미친다. 이러한 단음절어는 정상청력을 가진 사람도 말소리를 변별하는데 혼돈되는 단음절어들이 있다. 유방환 등은 박찬일 등의 498어음 중에서 출현빈도가 더 높고 음성학적으로 우리나라 일상 회화어음을 대표할 수 있다고 보이는 100개의 유의미단음절, 무의미단음절어로 된 어음을 뽑아 정상인과 여러 가지 난청형의 환자군을 대상으로 명료도와 오청현상을 연구하여 초성자음의 오청률이 종 성자음의 오청률보다 높다고 하였고, 초성자음과 모음의 오청현상은 박찬일의 결과와 유사하다고 하였다. 그리고 종성
The purpose of this study was to analyze the effects of redundancy changes in time and frequency domains (compression/expansion and high/low pass filtering) on discriminating monosyllabic words (CVC) under various signal to noise ratios (No noise, 10 dB, 0 dB, -10 dB SNR). Ten normal adult subjects participated in the study and three groups of “gom/gong”, “mal/bal”, and “sun/soon” sets were used as CVC word lists. In general, as the level of noise was increased, the ability of discriminating the listed set of words was deteriorated and this tendency was even pronounced under ipsilateral noise presentations. Changes in time and frequency domain clearly affected the discrimination performances of three test sets in conjunction with various levels of noise (SNR). The following main results were obtained from this experiment. 1) In ipsilateral presentation of noise, the lowest discrimination score was obtained in “gom/gong” set under the HIGH condition of redundancy change (i.e. highpass filtering in frequency). 2) In contralateral presentation of noise, the lowest discrimination score was recorded in “gom/gong” set as well and no statistically significant differences were observed in right and left sides of noise stimulation. 3) Even in normal subjects, discrimination of ending consonants (such as in gom/gong set) and initial consonants (such as in mal/bal set), and intermediate vowels (such as in sun/soon) were significantly influenced by the level of noise. Thus, in these data, it was suggested that the effects of the noise, together with time and frequency alterations, were critical in discriminating these CVC words. In conclusion, temporal changes in FAST/SLOW modes and spectral changes in LOW/HIGH modes could interact with the levels of SNR and the resultant combinations seemed to play critical roles in similar frequency bands in related phonemes. This kind of clinical data could be valuable in auditory training and rehabilitation for the hearing impaired. KEY WORDS：Monosyllabic words·Ipsilateral noise·Contralateral noise·Redundancy change.
INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSIONS CONCLUSIONS REFERENCES
