One of the most significant transitions reported in infant psychological development is perceptual narrowing whereby infants orient towards their native language. In monolingual infants, the progress made by infants in perceptual narrowing positively predicts later vocabulary size. The relationship between infant speech perception and later language development has not been thus far reported in bilingual populations. The present study investigated infant speech perception in relation to later vocabulary development in a prospective longitudinal study of bilingual infants over the first three years of life. Our study revealed three primary findings. First, unlike monolingual infants, bilingual infants demonstrated a positive correlation between native and non-native phonetic discrimination. Second, native speech perception at 10–11 months predicted single-language (English) vocabulary at 2 years, but not second language (Mandarin), nor total conceptual vocabulary. Third, infants with a native language orientation relative to a non-native orientation in phonetic discrimination at 10–11 months tended towards higher English vocabulary scores at 3 years of age. When placed in the context of prior research with monolingual infants, results with bilingual infants point to distinct relationships between native and non-native speech perception in infancy, but to a similar continuity between infant speech discrimination and later vocabulary growth.

据报道，婴儿心理发展中最重要的转变之一是感知范围的缩小，从而使婴儿适应他们的母语。在单语婴儿中，婴儿在知觉变窄方面所取得的进步积极地预测了以后的词汇量。迄今为止，双语人群中尚未报道婴儿语音感知与后来的语言发展之间的关系。本研究在一项对生命的头三年中双语婴儿进行的前瞻性纵向研究中，调查了与语音后来发展有关的婴儿语音感知。我们的研究揭示了三个主要发现。首先，与单语婴儿不同，双语婴儿在本地和非本地语音识别之间表现出正相关。第二，10-11个月的母语语音感知预测了2年的单语（英语）词汇量，但第二语言（普通话）的词汇量预测不到，概念词汇也没有。第三，在10到11个月时，母语相对于非母语的婴儿在语音识别方面相对于3岁时的英语词汇得分更高。当放在单语婴儿的先前研究中时，双语婴儿的研究结果表明婴儿期母语和非母语语音感知之间的独特关系，但指出婴儿语音歧视与后来词汇增长之间的相似连续性。在10到11个月的语音识别中，具有母语而非母语能力的婴儿在3岁时倾向于较高的英语词汇分数。当放在单语婴儿的先前研究中时，双语婴儿的研究结果表明婴儿期母语和非母语语音感知之间的独特关系，但指出婴儿语音歧视与后来词汇增长之间的相似连续性。在10到11个月的语音识别中，具有母语而非母语能力的婴儿在3岁时倾向于较高的英语词汇分数。当放在单语婴儿的先前研究中时，双语婴儿的研究结果表明婴儿期母语和非母语语音感知之间的独特关系，但指出婴儿语音歧视与后来词汇增长之间的相似连续性。