Speech intelligibility and spatial release from masking in anechoic and reverberant rooms: Comparison between German-speaking and Mandarin-speaking listeners

This study investigates the effects of masker and reverberation on the speech intelligibility and spatial release from masking (SRM) for tonal and non-tonal language speakers. Speech reception thresholds (SRTs) were measured in native Mandarin-Chinese-speaking (CMNS) and German-speaking (GS) normal hearing (NH) listeners using matrix sentence tests, in three virtual rooms with different reverberation times. Simulated bilateral cochlear implant (BiCI) users were also assessed under the same conditions. Reverberation had a stronger impact on SRTs and SRM with the international female fluctuating masker (IFFM) than with speech-shaped noise (SSN) for both NH groups and was more detrimental for simulated BiCI users. CMNS NH listeners exhibited significantly lower SRTs than GS listeners, but GS listeners showed larger SRM for IFFM. Reverberation exhibited a non-linear effect on SRT and SRM, especially for IFFM. CMNS listeners experienced greater SRT degradation in co-located conditions with reverberation. While both groups showed similar SRM degradation in the small reverberant room, CMNS listeners showed lower SRM without any further detrimental effect of stronger reverberation. Both CI processing and reverberation had a greater impact on SRTs for CMNS than GS. The simulated CMNS BiCI listeners showed lower SRTs than GS listeners for SSN, but SRM did not differ significantly.