Infant Statistical Learning in Natural Language Acquisition

描述(申请人提供)：婴儿擅长跟踪统计规律，在连续的语音中切分单词。研究人员使用高度简化的人工语言作为语音输入，记录了婴儿的学习能力。然而，自然语言充满了变异性。听演讲的婴儿会遇到不同的说话者、不同的词长和许多其他方面的复杂性。拟议的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。这项研究将提供一项严格的测试，以确定统计学习是否确实与早期语言习得有关。具体目标1是考察婴儿如何在给定发音类型的可变性的情况下切分单词--具体地说，是存在连续语音和孤立单词的情况。一项初步研究表明，孤立的单词可以提高婴儿在流利、自然的语音中对统计规律的注意力。实验一将检验这样一种假设，即孤立地听到单词有助于婴儿在连续的言语中发现其他单词。实验2将探索在语音不同的情况下的分词，测试当语音来自多个说话者时，孤立的单词是否能增强统计学习。具体目标2是调查语言经验的可变性如何影响婴儿随后对流利语音的统计规律的检测。在实验3中，婴儿将首先在实验室中短暂接触新的孤立单词。这种预熟悉预计会限制婴儿在连续语音中建立单词边界的能力。实验四将检验婴儿定向言语中多音节词所占比例的跨语言差异是否影响婴儿的分词能力。在第一年里，学习西班牙语的婴儿比学习英语的婴儿听到的多音节单词要多得多，他们在从连续语音中分割三音节单词的能力预计会比学习英语的婴儿更好。结果将评估以前的学习在多大程度上导致了促进处理未来语音的期望，或者婴儿的计算能力是否在每一时刻持续运行。这些研究的结果将为未来探索新发语言障碍儿童统计学习能力的研究提供参考。 公共卫生相关性：这项研究的目标是了解发育中的婴儿如何在他们从照顾者那里听到的复杂语言中发现结构。未来的研究将使用这些任务来评估表现出语言困难的儿童(例如，有特定语言障碍风险的儿童、患有紧急自闭症谱系障碍的儿童或植入人工耳蜗的聋子)的语言学习。最终目标是调查在这些临床人群中负责学习的机制是否受到损害，并开发更合适的工具用于早期诊断和干预。

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.