Decoding continuous speech in infancy

把语言习得看作是从儿童说出第一个有意义的单词开始的过程，忽视了语言发展的一个重要阶段。很久以前，婴儿甚至在接近于给单词赋予意义或产生语法话语之前，他们必须首先学习解码语音信号。成人言语知觉的研究表明，解码语音信号是一项复杂的任务，需要对语音信号进行深入的理解。甚至识别语音中的词边界也是具有挑战性的，因为没有可靠的词边界的声学提示(例如，词之间的静音)，并且没有词以相同的方式产生两次。尽管有这些困难，婴儿还是很早就开始识别单词了。目前的大多数语言习得模式都对婴儿从语言输入中提取规律性的能力造成了沉重的负担。已有大量研究支持这一关于早期语言发展的统计学习观点，但其中许多研究假设理想化的语音输入和成人对语音信号的关注。但这些假设不一定是合理的。在这个项目中，我将解决这些问题，目标是更好地将当前言语感知的发展模式与正常发育婴儿的真实感知和认知能力相结合。将解决的具体问题包括：1)婴儿是否比成年人更注意韵律；2)婴儿是否比其他环境更容易注意到发音错误；3)婴儿是否能像许多实验室研究中使用的简化语音一样，在真实语音中轻松跟踪统计模式。

Thinking of language acquisition as a process that begins when children utter their first meaningful words overlooks an important stage of language development. Long before infants are even close to attaching meanings to words or producing grammatical utterances, they must first learn to decode the speech signal. Research on adult speech perception has demonstrated that decoding the speech signal is a complicated task, requiring a sophisticated understanding of the speech signal. Even identifying word boundaries in speech is challenging because there are no reliable acoustic cues to word boundaries (e.g., silences between words), and no word is produced in an identical fashion twice. Despite these difficulties, infants begin recognizing words remarkably early. Most current models of language acquisition place a heavy burden on infants' ability to extract regularities from their language input. A great number of studies have been reported which support this statistical learning view on early language development, but many of these studies assume an idealized speech input and adult-like attention to the speech signal. But these assumptions are not necessarily justified. In this project, I will address these issues with the goal of better aligning current developmental models of speech perception with the real-life perceptual and cognitive capabilities of normally developing infants. Specific issues that will be addressed include 1) whether infants are more attentive to prosody than adults, 2) whether it is easier for infants to notice mispronunciations in some contexts than others, and 3) whether infants can track statistical patterns in real speech as easily as they do so with the simplified speech used in many laboratory studies.