Phonetic Features which Affect Native Japanese Speakers’ Syllable Perception

The present study examined the acoustic features that influenced syllable counting by Japanese learners of English. Drawing on Katayama’s (2025) findings from a syllable-counting task using spoken English words ranging from one to five syllables, regression analyses were conducted to determine which factors predicted participants’ syllable perception. The predictors included the actual number of syllables, the number of phonemes, word duration, syllable duration, the standard deviation of phoneme duration, and segmental features (plosives, nasals, liquids, lax vowels, tense vowels), as well as vowel types when the English words were converted into loanwords in katakana. The results indicated that the actual number of syllables was the strongest predictor, followed by the number of phonemes. Further analyses showed that tense vowels contributed to syllable perception, whereas plosives, nasals, and liquids were associated with a decrease in the number of perceived syllables. These findings suggest that Japanese listeners counted syllables in English words not according to mora but according to phonetic salience.