The clear speech effect for non-native listeners

Area of Science:

• Speech Perception
• Auditory Neuroscience
• Second Language Acquisition

Background:

• Previous research indicates clear speech enhances intelligibility for native and hearing-impaired listeners in noisy environments.
• Clear speech involves slower articulation, increased pitch range, and precise consonant production.

Purpose of the Study:

• To evaluate the effectiveness of naturally produced clear speech as an intelligibility enhancement strategy for non-native English listeners.
• To compare the benefits of clear speech for non-native listeners versus native listeners.

Main Methods:

• 32 non-native and 32 native English listeners participated.
• Participants listened to English sentences produced in either conversational or clear speaking styles.
• Stimuli were presented at two signal-to-noise ratios (-4 dB and -8 dB) by a male and female talker.

Main Results:

• Native listeners showed a substantial improvement in intelligibility with clear speech (approx. 16 rau units).
• Non-native listeners exhibited a significantly smaller benefit from clear speech (approx. 5 rau units).

Conclusions:

• Naturally produced clear speech is less effective for non-native listeners compared to native listeners.
• The benefits of clear speech are limited for non-native listeners due to its orientation towards native phonological and prosodic patterns.