The importance of the first syllable in English spoken word recognition by adult Japanese speakers

Abstract

We investigated adult Japanese speakers’ deficiencies in English spoken word recognition. We found that the accurate recognition of the first syllable or the initial portion of each word played an important role in recognizing a word correctly. It was implied in the study that their recognition performance would be enhanced by utilizing the speech processing methods, time-scale expansion and/or dynamic range compression. Although approximately 85 percent of English words begin with strong syllables [1], many of them do not carry a sentence stress and they are not pronounced as clearly as isolated words. Moreover, the duration of a word, especially a beginning word is so short that the listener can't recognize it correctly. Two experiments were administered in the anechoic room. In the first experiment, subjects listened to extracted words and corresponding isolated words of English, which included words without primary stress on the first syllables. We found that they had difficulty in recognizing both isolated words and the extracted words, especially when the word did not begin with a strong syllable, which was sounded somewhat unclear. This is quite frequent in a normal English speech. We confirmed that they had difficulty recognizing the words which began with weak syllables and it is concluded that the first syllable plays an important role in the recognition of words at least for Japanese speakers. In the second experiment, the extracted words and the corresponding time-scale expanded words (henceforth, expanded words) were given. The result indicated that the expanded words were better recognized. It is found that the time-scale modification (henceforth, TSM) of the extracted words didn’t lose intelligibility even around the ratio of 2.00, as was clear from the fact that the recognition improved.