Stuart Andrew, Zhang Jianliang, Swink Shannon
Department of Communication Sciences and Disorders, Mail Stop 668, East Carolina University, Greenville, NC 27858-4353, USA.
J Am Acad Audiol. 2010 Apr;21(4):239-48. doi: 10.3766/jaaa.21.4.3.
Bilingual (BL) listeners' difficulties in adverse noise conditions are exacerbated when perceiving their second language (L2) relative to their first language (L1). Perception of L2 is also significantly poorer by BL listeners compared to native monolingual (ML) listeners.
The purpose of the study was to examine the effect of stationary and nonstationary energetic noise maskers on L1 and L2 speech perception in native and nonnative listeners.
A mixed multivariate quasi-experimental design was employed.
Two groups of 12 ML English-speaking and BL Mandarin-English-speaking normal-hearing young adult female volunteers participated.
An adaptive technique was employed to determine reception thresholds for sentences (RTSs) in quiet and in backgrounds of competing continuous and interrupted noise. The noises differed only in their temporal continuity. The sentence stimuli employed consisted of the Hearing in Noise Test (HINT) and the Mandarin Hearing in Noise Test (MHINT). ML participants received the HINT stimuli while the BL participants received both HINT and MHINT stimuli. Between-group differences in RTSs were examined for the same stimuli (i.e., HINT) and for L1 stimuli (i.e., HINT vs. MHINT). Within-group differences in RTSs were examined with the BL participants' perception of L1 and L2 stimuli (i.e., MHINT vs. HINT). The amount of "release from masking" (i.e., the difference of RTS signal-to-noise ratios [SNRs] in interrupted and continuous noise) was also examined between and within groups.
In quiet there was no significant difference in mean RTSs between the BL and ML participants with their respective L1 stimuli; MLs had significantly lower mean RTSs in English compared to the BLs; and mean RTSs for the BLs were significantly lower for L1 versus L2 stimulus. In noise, a significantly higher RTS SNR was found for the MLs in continuous noise but not interrupted noise for L1 stimuli compared to the BLs; BLs had a significantly higher mean RTSs in English compared to the MLs; and BLs had significantly higher mean RTSs for L2 versus L1 stimuli. The release from masking was significantly greater for MLs compared to BLs with their respective L1 stimuli and with the same English stimuli. There was no significant difference for the BLs' release from masking with L1 versus L2 stimulus.
BL listeners display significantly poorer performance when perceiving nonnative L2 sentences in quiet and in continuous and interrupted noise relative ML listeners. When listening to their respective native L1 sentences, only a difference in continuous noise was found. This difference was attributed to differential masking effect on the English stimuli. Similar performance in the interrupted noise between the ML and BL participants with L1 stimuli and the equivalent release from masking with the BL participants for both L1 and L2 stimuli suggest comparable basic auditory temporal resolving capacities between these ethnic groups.
双语（BL）听众在不利噪声条件下感知其第二语言（L2）时，相对于其第一语言（L1），困难会加剧。与以母语为单语的（ML）听众相比，双语听众对L2的感知也明显更差。
本研究的目的是检验固定和非固定能量噪声掩蔽器对母语和非母语听众L1和L2语音感知的影响。
采用混合多变量准实验设计。
两组各有12名听力正常的年轻成年女性志愿者参与，一组是以英语为母语的单语者（ML），另一组是说普通话和英语的双语者（BL）。
采用自适应技术确定在安静环境以及连续和间断噪声背景下句子的接受阈值（RTS）。这些噪声仅在时间连续性上有所不同。所使用的句子刺激包括噪声中的听力测试（HINT）和普通话噪声中的听力测试（MHINT）。ML参与者接受HINT刺激，而BL参与者接受HINT和MHINT刺激。针对相同刺激（即HINT）以及L1刺激（即HINT与MHINT），检验RTS组间差异。针对BL参与者对L1和L2刺激的感知（即MHINT与HINT），检验RTS组内差异。还在组间和组内检验了“掩蔽释放量”（即间断噪声和连续噪声中RTS信噪比[SNR]的差异）。
在安静环境中，BL和ML参与者在各自的L1刺激下，平均RTS没有显著差异；与BL参与者相比，ML参与者的英语平均RTS显著更低；对于BL参与者，L1刺激的平均RTS显著低于L2刺激。在噪声环境中，与BL参与者相比，ML参与者在连续噪声而非间断噪声中，对于L1刺激有显著更高的RTS SNR；与ML参与者相比，BL参与者的英语平均RTS显著更高；对于BL参与者，L2刺激的平均RTS显著高于L1刺激。与各自的L1刺激以及相同的英语刺激相比，ML参与者的掩蔽释放量显著大于BL参与者。BL参与者L1与L2刺激的掩蔽释放量没有显著差异。
与ML听众相比，BL听众在安静环境以及连续和间断噪声中感知非母语L2句子时表现明显更差。在听各自的母语L1句子时，仅在连续噪声中发现差异。这种差异归因于对英语刺激的不同掩蔽效应。ML和BL参与者在L1刺激的间断噪声中有相似表现，且BL参与者在L1和L2刺激下有同等的掩蔽释放量，这表明这些种族群体之间具有可比的基本听觉时间分辨能力。
