Effects of delayed auditory feedback on consonant, vowel, and mora timing in Japanese speech

This study investigates changes in the rhythmic characteristics of Japanese speech induced by delayed auditory feedback (DAF). Ten native speakers read sentences under four DAF conditions (0, 100, 200, and 300 ms), and interval durations (consonant, vowel, and mora) were measured. Speech rhythm indices were evaluated using Mean (average duration), Delta (absolute variability), and Varco (relative variability). DAF increased Mean and Delta in consonant and vowel durations, indicating greater temporal variability at the phoneme level. However, the relative isochrony of morae, measured by VarcoM, remained stable, suggesting mora timing tends to be preserved under feedback perturbations.