Speech rate and the perception of consonant and vowel length in Japanese: Neural entrainment and episodic memory

Neural entrainment (the persistence of speech rhythm-dependent neural oscillations) and episodic memory-based perception (exemplar theory and belief-updating models) have been proposed to explain speech rate-dependent perception. To test these accounts, we examined the rate-dependent perception of Japanese vowel and stop length contrasts while varying speech rate by manipulating all segments, vowels only, or consonants only in the carrier sentence. Robust rate effects were observed across all conditions, consistent with the neural entrainment account. In addition, the manipulation method modulated rate effects for stops but not for vowels, offering partial support for the episodic account.