The common limitations in auditory temporal processing for Mandarin Chinese and Japanese

Area of Science:

• Auditory Neuroscience
• Speech Processing
• Psychoacoustics

Background:

• Temporal processing is crucial for speech intelligibility.
• Understanding how temporal degradation affects different language types is important.

Purpose of the Study:

• To investigate the effect of temporal degradation on speech intelligibility in Mandarin Chinese (tonal) and Japanese (non-tonal).
• To explore the underlying temporal processing mechanisms in speech perception.

Main Methods:

• Systematic temporal degradation of speech using mosaicking (averaging power in time-frequency units and removing temporal fine structure).
• Assessing intelligibility across varying segment durations for both languages.
• Employing local time-reversal as a secondary degradation method.

Main Results:

• Intelligibility showed similar patterns for both tonal and non-tonal languages.
• A performance ceiling was maintained up to ~40 ms segment duration.
• Intelligibility gradually declined beyond 40 ms, reaching a floor around 150 ms or longer.
• Similar limitations were observed with local time-reversal, suggesting a common temporal processing mechanism.

Conclusions:

• Temporal degradation critically affects speech cues beyond tonal information.
• Speech intelligibility is constrained by temporal processing limitations, consistent with a dual time-window model (~20-30 ms and ~200 ms).
• A common temporal processing mechanism underlies speech perception across different language types.