SPEECH INTELLIGIBILITY BY USE OF NEW WORD-LISTS WITH CONTROLLED WORD FAMILIARITIES AND A PHONETIC BALANCE

摘要

For optimal design of speech communication systems, it is very important to evaluate the quality and/or performance of the systems. Until now, nonsense monosyllables have been used to measure speech intelligibility in Japanese. However, results obtained by this method often fail to reflect the personal acuity since people hardly hear nonsense monosyllables. Therefore, we developed a new word intelligibility test in which we well considered not only the phonetic balance but also the degree of difficulty of words. Though word frequency is often used as the index of difficulty, it does not correctly reflect subjective difficulties of words. Thus we used word familiarity, which has been shown as a good index of subjective difficulty of words, instead of word frequency. Moreover, we balanced the phonemes by regarding the sequence of a vowel and a following consonant in words. The word intelligibility was then tested with normal listeners to evaluate the performance of the lists. The results indicated that the word intelligibility expectedly depend on the word familiarities. This suggests that our new method may be useful and powerful to assess the personal acuity of speech understanding from various viewpoint by using word lists with different word familiarities.