Effects of Signal to Noise Ratios on Japanese Pitch Accent Perception and Pitch Pattern Discrimination

Abstract

This study aimed to analyze the effects of noise with various signal to noise ratios on suprasegmental features (pitch accent) in Japanese double mora words in native (Japanese) and non-native (Korean) groups. Pitch pattern discrimination test with High-Low and Low-High patterns (195 Hz/270 Hz, 195 Hz/205 Hz, 270 Hz/280 Hz) and Japanese pitch accent perception test with 10 pairs of Japanese double mora nouns were presented to Japanese and Korean subjects under various signal to noise ratios. The results were as follows：(1) There were no significant effects of noise on pitch pattern test in Japanese group while Korean group showed statistically significant effects at 195 Hz/270 Hz, 270 Hz/280 Hz patterns at –10 dB SNR (p=0.05). Japanese accent perception test showed statistically significant effects at -5, -10 dB SNRs in both groups. (2) There were no statistically significant effects of the native language on pitch pattern discrimination test while Japanese pitch accent perception test exhibited statistically significant effects at - 10 dB SNR. In addition, the correct response rates of Japanese group were higher than those of Korean group in individual words. (3) In Japanese group both LH and HL patterns had similar correct response rates while in Korean group HL pattern showed better performances than LH pattern. (4) There was no statistically significant correlation between the degree of fundamental frequency differences and correct scores in double morae. The corresponding slope profile of correct scores vs SNR ratios was steeper in Korean than Japanese group. KEY WORDS：SNR·Japanese pitch·Pitch accent·Pitch pattern