The development of phonetic perception

本研究计划通过对元音感知的调查，探索婴儿期言语感知的发展。我们的目标是全面描述幼儿在言语反应中表现出的元音知觉偏差，解释这些知觉偏差是如何以及何时在发育过程中形成的，并确定它们在口语习得中的作用。在追求这些目标的过程中，我们将测试和阐述一个新的概念模型，自然参照元音(NRV)框架。根据这一观点，具有特定发音声学特性的元音(这也定义了传统元音空间中的外围元音)充当了一个自然的参照物：它们通过吸引婴儿的注意力和为学习者建立一个稳定的参照系来支持和指导元音感知的发展。先前关于婴儿对不同元音的听力偏好的研究表明，婴儿(4至12个月大)对外围元音有强烈的知觉偏向，从而支持了这一观点。研究1将评估这种知觉偏差最初是在婴儿期何时形成的(以及如何形成的)。我们将对两个月大的婴儿和新生儿进行比较，以评估这一假设，即元音感知偏差是通过婴儿神经听觉能力和言语暴露之间的相互作用在生命早期出现的。研究2和研究3将验证NRV的说法，即外围元音支持元音感知和产生的发展。研究二通过测试婴儿对说话者发出的元音的偏好(使用一种新的元音合成工具)来测试元音感知偏差也会影响婴儿感知自己的发声模式的预测。研究三将评估婴儿识别不同说话者(成人、儿童、婴儿)产生的相同元音的能力，以检验NRV预测，即元音分类技能是以一种循序渐进的方式发展的，因此外围元音类别比非外围元音类别更容易获得，并且先于非外围元音类别获得。这将是第一个研究婴儿如何感知婴儿产生的声音信号的研究。这种方法是理解说和听技能在婴儿言语发展中如何相互作用所必需的。

This research program explores the development of speech perception in infancy through investigations that focus on vowel perception. Our goal is to fully portray vowel perception biases that young infants display in response to speech, explain how and when these perceptual biases form in development, and establish their role in the acquisition of spoken language. In pursuing these goals we will test and elaborate a new conceptual model, the Natural Referent Vowel (NRV) framework. According to this view, vowels with specific articulatory-acoustic properties (which also define the peripheral vowels in a traditional vowel space) act a natural referents: they support and guide the development of vowel perception by attracting infant attention and establishing a stable frame of reference for the learner. Prior studies of infant listening preferences for different vowels support this view by showing that infants (4 to 12 months of age) have a strong perceptual bias favoring peripheral vowels. Study 1 will assess when (and how) this perceptual bias is initially formed in early infancy. We will compare 2-month-olds and newborns to assess the hypothesis that vowel perception biases emerge early in life via an interaction between infant neuro-auditory abilities and speech exposure. Studies 2 and 3 will test the NRV claim that peripheral vowels support the development of vowel perception and production. Study 2 tests the prediction that vowel perception biases also impact how babies perceive their own vocal patterns by examining infant listening preferences for vowels produced by an infant talker (using a new vowel synthesis tool). Study 3 will assess infant ability to recognize the same vowel produced by different talkers (adult, child, infant) to test the NRV prediction that vowel categorization skills develop in a stepwise, hierarchical manner such that peripheral vowel categories are acquired more easily and prior to non-peripheral vowel categories. This will be the first study to investigate how infants perceive infant-produced vocal signals. This approach is needed to understand how speaking and listening skills interact in infant speech development.