Effect of speaking rate variation on the perception of singleton and geminate consonants in Japanese by native and Korean listeners

Perception of phonemic length contrasts in Japanese is difficult for non-native listeners. To better understand the source of this difficulty, the present study investigated native Korean listeners' perception of consonant length contrasts at different speaking rates. Stimuli were created by modifying the duration of the second consonant of /ereC:e/ along a continuum to /ereCe/, where C was /k/ or /s/. The base words were spoken by a professionally trained native Japanese speaker with a carrier sentence at three rates, fast, normal, slow. Twenty four native Korean and twelve native Japanese listeners participated in a perception test. They listened to one of the created stimuli and identified whether the second consonant was singleton or geminate. Results show that even though Korean listeners' perceptual boundary position between singleton and geminate consonants shifted according to speaking rate in a similar manner as the natives, their boundary width was more variable and larger than native listeners ...