Infants can discriminate languages that belong to different rhythmic classes at birth. The ability to perform within-class discrimination emerges around the fifth month of life. The cues that infants use to discriminate between prosodically close languages remain elusive. Segmental information could be a potential cue, since infants notice vowel mispronunciations of their names, show the first signs of word recognition and the first signs of perceptual narrowing for vowels around 6 months of age. If infants have in place some proto-segmental information, most likely it is about vowels. Another potential cue infants may use to discriminate languages is intonation. We tested participants using sentences in Eastern Catalan, Western Catalan and Spanish. The two Catalan dialects and Spanish belong to the same rhythmic class, they are syllable-timed, but they differ in terms of vowel distribution, given that only Eastern Catalan has vocalic reduction. The vowel distributions of Western Catalan and Spanish are more comparable. However, they differ in terms of their intonational patterns. In Experiment 1, we tested the ability of 4.5-month-old infants learning Eastern Catalan and/or Spanish to discriminate between sentences in Eastern and Western Catalan and in Experiment 2 their ability to discriminate between sentences in Western Catalan and Spanish. In order to disentangle the contribution of segmental and suprasegmental information, we also tested infants using low-pass filtered sentences in the two dialects (Experiment 3) and low-pass filtered sentences in Western Catalan and Spanish (Experiment 4). Infants discriminated the two Catalan dialects only when the stimuli were natural sentences, whereas they were able to discriminate between Western Catalan and Spanish when the stimuli were either natural or low-pass filtered sentences. The research also provides evidence of equivalent language discrimination abilities in infants growing up in monolingual and bilingual environments.

婴儿在出生时就可以区分属于不同节奏类别的语言。执行阶级内歧视的能力出现在生命的第五个月左右。婴儿用来区分韵律接近的语言的线索仍然难以捉摸。句段信息可能是一个潜在的线索，因为婴儿会在 6 个月左右注意到他们名字的元音发音错误，显示出单词识别的第一个迹象和元音感知变窄的第一个迹象。如果婴儿有一些原始音段信息，很可能是关于元音的。婴儿可能用来区分语言的另一个潜在线索是语调。我们使用东加泰罗尼亚语、西加泰罗尼亚语和西班牙语的句子测试参与者。两种加泰罗尼亚方言和西班牙语属于同一个韵律类，它们是音节定时的，但它们在元音分布方面有所不同，因为只有东加泰罗尼亚语有声音减少。西加泰罗尼亚语和西班牙语的元音分布更具可比性。然而，它们在语调模式方面有所不同。在实验 1 中，我们测试了学习东加泰罗尼亚语和/或西班牙语的 4.5 个月大的婴儿区分东加泰罗尼亚语和西加泰罗尼亚语句子的能力，以及在实验 2 中他们区分西加泰罗尼亚语和西班牙语句子的能力。为了弄清分段和超分段信息的贡献，我们还使用两种方言中的低通过滤句子（实验 3）和加泰罗尼亚语和西班牙语中的低通过滤句子（实验 4）对婴儿进行了测试。只有当刺激是自然句子时，婴儿才能区分两种加泰罗尼亚方言，而当刺激是自然或低通过滤的句子时，他们能够区分西加泰罗尼亚语和西班牙语。该研究还提供了在单语和双语环境中长大的婴儿具有同等语言辨别能力的证据。