Learning Mechanisms in Early Vocal Development

达到规范的牙牙学语阶段（平均在7个月）是一个重要的里程碑：在这个年龄段，婴儿开始产生辅音-元音音节，这是口语的基本组成部分。我实验室的研究涉及不同程度听力损失的婴儿，研究表明，在出生后的第一年，听到成年人说话是实现语言样牙牙学语的关键。此外，学习英语、法语和阿拉伯语的婴儿，学习牙牙学语的方式也有微妙的不同。宝宝是如何学习具有母语声音特征的牙牙学语的？我建议测试一个模型的语言运动学习，婴儿学会感知语音类别听到的讲话，并试图产生这些类别时，咿呀学语。婴儿的动机，以减少错误的匹配之间的内在感知类别和言语期间产生的牙牙学语。成人看护者的语音输入（a）提供有关母语语音类别的信息，（B）鼓励发声探索，（c）加强语音练习。这种模式可以与另一种模式形成对比，在这种模式中，当成年人模仿类似于成人语言中的语音类别的婴儿语音时，类似于婴儿语音的话语被加强。这项研究计划的目的之一是描述成人和他们的婴儿在三种情况下的模仿模式：（1）听力正常的婴儿和他们说英语的母亲;（2）听力正常的婴儿和他们说阿拉伯语的母亲;（3）听力受损的婴儿，人工耳蜗植入，与他们说阿拉伯语的母亲互动。我们预计，母亲模仿发生的频率将远远低于目前的一些计算机模型的语音发展预测，并发现母亲调整自己的语音反应的意义，他们的婴儿的输出。 在第二项研究中，我们将教婴儿产生外语元音，提供接触外语，但没有模仿或扩大婴儿的话语。与对照组相比，婴儿对外语声音类别的感知和产生的变化将被描述。我们假设，这些结果将支持内在动机和自我监督学习作为支持语音学习的机制。理解言语产生是如何发展的，在言语治疗和口音减轻等领域一直有重要的应用。最近，婴儿语音产生的研究已被应用于语音识别和合成，机器学习和机器人领域。理论账户目前正在通过机器学习模型进行测试，而没有足够的人类数据来指导其实施或验证其输出。这项研究计划将产生大量详细的语音和声学数据样本，描述不同条件下婴儿的声音输出。

Achievement of the canonical babbling stage (on average at 7 months) is an important milestone: at this age the infant begins to produce consonant-vowel syllables that are the fundamental building blocks of spoken language. Research from my lab, involving infants with varying levels of hearing loss, shows that hearing speech from adult talkers is essential to achieving speech-like babble in the first year of life. Furthermore, babies learning English, French, and Arabic, learn to babble in subtly different ways. How do babies learn to babble with native language sound characteristics? I propose to test a model of speech motor learning in which the infant learns to perceive speech categories from heard speech and attempts to produce those categories when babbling. The baby is motivated to reduce errors in the match between internalized perceptual categories and speech produced during babble. Speech input from adult caregivers (a) provides information about native-language speech categories, (b) encourages vocal exploration, and (c) reinforces speech practice. This model can be contrasted with an alternative model in which speech-like infant utterances are reinforced when adults mimic infant speech that is similar to speech categories in the adult language. One aim of this research program is to describe patterns of mimicry between adults and their infants in three contexts: (1) normal hearing infants and their English-speaking mothers; (2) normal hearing infants and their Arabic speaking mothers; (3) hearing impaired infants, with cochlear implants, in interaction with their Arabic speaking mothers. We expect that maternal mimicry will occur much less frequently than is predicted by some current computer models of speech development and to find that mothers adjust their speech responses to the meaningfulness of their infant's outputs. In a second study we will teach infants to produce foreign language vowels by providing exposure to the foreign language, but without imitating or expanding infant utterances. Changes in the infants' perception and production of foreign language sound categories will be described in comparison to a control group. We hypothesize that the results will support intrinsic motivation and self-supervised learning as mechanisms that support speech learning. Understanding how speech production develops has always had important applications in fields such as speech therapy and accent reduction. More recently, infant speech production research has been applied in the areas of speech recognition and synthesis, machine learning and robotics. Theoretical accounts are currently being tested via machine learning models without the benefit of sufficient human data to guide their implementation or validate their outputs. This research program will produce large samples of detailed phonetic and acoustic data describing infant vocal output under varying conditions.