Infant Statistical Learning in Natural Language Acquisition

描述（申请人提供）：幼儿善于追踪统计规律，在连续言语中分词。研究人员已经记录了婴儿使用高度简化的人工语言作为语音输入的学习能力。然而，自然语言充满了可变性。婴儿在听语音时，会遇到不同的说话者、不同的单词长度和许多其他复杂的维度。该实验将使用捕捉婴儿语言环境中观察到的自然变化的关键方面的语音来测试婴儿是否使用统计学习机制来识别单词边界。这项研究将为统计学习是否与早期语言习得有关提供一个严格的测试。具体目标1是研究婴儿如何在话语类型变化的情况下分割单词，特别是连续语音和孤立单词的存在。一项初步研究表明，在流利、自然的言语中，孤立的单词可以增强婴儿对统计规律的注意。实验1将检验一个假设，即孤立地听单词有助于婴儿在连续的言语中发现其他单词。实验2将探讨基于语音变化的分词，测试当语音来自多个说话者时，孤立的单词是否会增强统计学习。具体目标2是研究语言经验的可变性如何影响婴儿对流利言语的统计规律的后续检测。在实验3中，婴儿将首先在实验室中短暂地接触到新的孤立单词。这种预熟悉被认为会限制婴儿在连续讲话中建立单词边界的能力。实验4将检验婴儿指向性言语中多音节词所占比例的跨语言差异是否会影响婴儿的分词能力。学西班牙语的婴儿在第一年听到的多音节单词比学英语的婴儿多得多，他们在从连续语音中分割三音节单词方面比学英语的婴儿表现出更强的能力。研究结果将评估以前的学习在多大程度上导致了对未来语言处理的预期，或者婴儿的计算能力是否在每个时刻都持续运行。这些研究的结果将为未来探索具有突发性语言障碍的幼儿的统计学习能力的研究提供信息。

DESCRIPTION (provided by applicant): Infants are adept at tracking statistical regularities to segment words in continuous speech. Researchers have documented infants' learning abilities using highly simplified artificial languages as speech input. However, natural language is replete with variability. Infants listening to speech encounter different speakers, different word lengths, and numerous other dimensions of complexity. The proposed experiments will use speech that captures key aspects of the natural variation observed in infants' language environments to test whether infants use statistical learning mechanisms in identifying word boundaries. This research will provide a rigorous test of whether statistical learning is in fact linked to early language acquisition. Specific Aim 1 is to examine how infants segment words given variability in utterance types-specifically, the presence of both continuous speech and isolated words. A preliminary study showed that isolated words enhance infants' attention to statistical regularities in fluent, natural speech. Experiment 1 will test the hypothesis that hearing words in isolation helps infants discover other words in continuous speech. Experiment 2 will explore word segmentation given variation in voices, testing whether isolated words enhance statistical learning when speech comes from multiple talkers. Specific Aim 2 is to investigate how variability in language experience influences infants' subsequent detection of statistical regularities in fluent speech. In Experiment 3, infants will first receive brief laboratory exposure to novel isolated words. This pre-familiarization is expected to constrain infants' abilities to establish word boundaries in continuous speech. Experiment 4 will test whether cross-linguistic differences in the proportion of multisyllabic words in infant-directed speech shape infants' word segmentation abilities. Spanish-learning infants, who hear far more multisyllabic words than English-learning infants over the first year, are expected to show greater facility in segmenting trisyllabic words from continuous speech than English-learning infants. The results will assess the degree to which previous learning leads to expectations that facilitate processing future speech, or whether infants' computational abilities operate continuously at each moment in time. The outcomes of these studies will inform future research exploring statistical learning abilities in young children with emergent language impairments. PUBLIC HEALTH RELEVANCE: The goal of this research is to understand how typically developing infants discover structure in the complex speech they hear from caregivers. Future studies will use these tasks to assess language learning in children exhibiting difficulties with language (e.g., children at risk for specific language impairment, children with emergent autism spectrum disorder, or deaf children with cochlear implants). The eventual goals are to investigate whether the mechanisms responsible for learning are compromised in these clinical populations, and to develop more appropriate tools for early diagnosis and intervention.