Some listeners exhibit higher sensitivity to subphonemic acoustic differences (i.e., higher speech gradiency). Here, we asked whether higher gradiency in a listener's first language (L1) facilitates foreign language learning and explored the possible sources of individual differences in L1 gradiency. To address these questions, we tested 164 native Spanish speakers with different linguistic profiles. Speech gradiency was assessed via a Visual Analogue Scale task, and foreign language proficiency was assessed via an English vocabulary test. Possible sources of gradiency included domain‐general auditory acuity, overall exposure to spoken language (indexed by age), and exposure to phonological diversity. Control measures were collected to account for variables such as phoneme categorization consistency, working memory, and musical training. The results revealed a positive link between L1 speech gradiency and vocabulary acquisition in a foreign language over and above all other variables. L1 speech gradiency itself was predicted by domain‐general auditory acuity and overall exposure to spoken language.

中文翻译：

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对第一语言亚音素差异的敏感性可预测外语的词汇量

一些听众对亚音素声学差异表现出更高的敏感性（即更高的语音梯度）。在这里，我们询问听者的第一语言 (L1) 的较高梯度是否有利于外语学习，并探讨了 L1 梯度个体差异的可能来源。为了解决这些问题，我们对 164 名具有不同语言背景的西班牙语母语者进行了测试。通过视觉模拟量表任务评估言语梯度，通过英语词汇测试评估外语能力。梯度的可能来源包括一般领域的听觉敏锐度、口语的总体暴露程度（按年龄索引）以及语音多样性的暴露程度。收集控制措施来解释音素分类一致性、工作记忆和音乐训练等变量。结果表明，与其他变量相比，第一语言语音梯度与外语词汇习得之间存在正相关关系。 L1 语音梯度本身是通过领域通用听觉敏锐度和总体口语暴露程度来预测的。