Blasingame Michael, Bradlow Ann R
Department of Linguistics, Northwestern University, Evanston, IL 60208, USA.
Languages (Basel). 2020 Dec;5(4). doi: 10.3390/languages5040039. Epub 2020 Oct 18.
Both the timing (i.e., when) and amount (i.e., how much) of language exposure affect language-learning outcomes. We compared speech recognition accuracy across three listener groups for whom the order (first versus second) and dominance (dominant versus non-dominant) of two languages, English and Spanish, varied: one group of Spanish heritage speakers (SHS; L2-English dominant; L1-Spanish non-dominant) and two groups of late onset L2 learners (L1-dominant English/Spanish learners and L1-dominant Spanish/English learners). Sentence-final word recognition accuracy in both English and Spanish was assessed across three "easy" versus "difficult" listening conditions: (1) signal-to-noise ratio (SNR; +5 dB SNR versus 0 dB SNR), (2) sentence predictability (high versus low sentence predictability), and (3) speech style (clear versus plain speech style). Overall, SHS English recognition accuracy was equivalent to that of the L1-dominant English Spanish learners, whereas SHS Spanish recognition accuracy was substantially lower than that of the L1-dominant Spanish English learners. Moreover, while SHS benefitted in both languages from the "easy" listening conditions, they were more adversely affected by (i.e., they recognized fewer words) the presence of higher noise and lower predictability in their non-dominant L1 Spanish compared to their dominant L2 English. These results identify both a benefit and limit on the influence of early exposure. Specifically, the L2-dominant heritage speakers displayed L1-like speech recognition in their dominant-L2, as well as generally better recognition in their non-dominant L1 than late onset L2 learners. Yet, subtle recognition accuracy differences between SHS and L1-dominant listeners emerged under relatively difficult communicative conditions.
语言接触的时间（即何时）和数量（即多少）都会影响语言学习的成果。我们比较了三组听众的语音识别准确率，这三组听众两种语言（英语和西班牙语）的顺序（第一语言与第二语言）和主导性（主导语言与非主导语言）各不相同：一组是西班牙裔说西班牙语者（SHS；第二语言英语为主导；第一语言西班牙语为非主导），两组是晚学第二语言者（第一语言英语/西班牙语为主导的学习者和第一语言西班牙语/英语为主导的学习者）。在三种“简单”与“困难”的听力条件下评估了英语和西班牙语句子末尾单词的识别准确率：（1）信噪比（SNR；+5 dB SNR与0 dB SNR），（2）句子可预测性（高句子可预测性与低句子可预测性），以及（3）语音风格（清晰语音风格与普通语音风格）。总体而言，西班牙裔说西班牙语者的英语识别准确率与第一语言英语为主导的西班牙语学习者相当，而西班牙裔说西班牙语者的西班牙语识别准确率则大大低于第一语言西班牙语为主导的英语学习者。此外，虽然西班牙裔说西班牙语者在两种语言中都从“简单”听力条件中受益，但与他们的主导第二语言英语相比，他们在非主导第一语言西班牙语中受到更高噪音和更低可预测性的负面影响更大（即他们识别的单词更少）。这些结果确定了早期接触的益处和局限性。具体而言，第二语言为主导的西班牙裔说西班牙语者在其主导的第二语言中表现出类似第一语言的语音识别能力，并且在其非主导的第一语言中通常比晚学第二语言者的识别能力更好。然而，在相对困难的交流条件下，西班牙裔说西班牙语者与第一语言为主导的听众之间出现了细微的识别准确率差异。
