Gesture as a forerunner of linguistic change: insights from autism

在正常发育的儿童中，手势是语言发展的先导。孩子们最初会说句子，后来会使用手势和语言的组合来扩展语言（叙述、解释），然后完全用语言表达相同的意思。该项目旨在确定手势是否也可以作为自闭症谱系障碍（ASD）儿童迅速发展的口语能力的可靠指标，这些儿童在达到类似的里程碑时表现出延迟和/或偏差。本项目通过纵向观察研究语言发展的两个关键阶段的手势和言语使用，即请求和评论句子的开始（研究1）和叙述和解释中扩展言语的开始（研究2），来解决这个问题。研究1的重点是第一个句子，研究了18名自闭症儿童和18名正常发育儿童在两种语言环境下（评论物体和请求物体）从生成单个单词过渡到生成简单句子时手势和语言的变化。研究2的重点是扩展语言，研究了25名自闭症儿童和25名正常发育儿童在两种语言环境下的手势和语言变化：叙述和解释。考虑到自闭症儿童在早期表现出的手势制作困难，以及随后的语言制作延迟，该项目想知道，导致早期句子和后来的叙述/解释的手势-语言组合模式是否被打乱了，或者这种语言学习过程是否如此强大，以至于自闭症儿童和正常发育的儿童一样，最初依靠手势和语言一起来传达他们新兴的口语能力。本研究将在两个主要方面做出重要贡献：第一，研究结果将为语言发展理论提供有关不同学习者手势语音系统鲁棒性的信息。与正常发育的儿童相比，ASD儿童的语言学习轨迹表现出差异，在早期评论和后期叙述情境中表现出弱势，在早期请求和后期解释情境中表现出相对优势。自闭症儿童在早期的指指手势方面也表现出独特的缺陷，但在后期的标志性手势方面却表现出相对优势，这使他们成为了解手势是否以及如何成为跨阶段和语言习得背景下支持语言学习的发展过程的一部分的理想群体。其次，这些发现具有潜在的临床意义。当考虑到伴随的言语时，手势可以用来识别孩子在语言里程碑方面处于过渡状态。更具体地说，那些用手势和语言传达不同信息的孩子更愿意学习，反过来，他们也更有可能从教学中受益。因此，手势可以作为新兴语言能力的一个很好的指标，反过来，它可以帮助教育工作者和临床医生确定最佳时机，为那些发展迟缓或异常的儿童引入特定任务的语言学习策略。这些策略的范围可以从提供更有针对性的口语输入到明确鼓励儿童在谈论他们处于学习尖端的概念时使用特定的手势——这两种策略都被证明是向正常发育的儿童教授新概念的有效策略。

Gesture acts as a forerunner of language development in typically developing children. Children take their initial steps into sentences, and later, into extended speech (narratives, explanations) using gesture-speech combinations before expressing the same meanings entirely in speech. This project aims to determine whether gesture also serves as a reliable index of burgeoning spoken language abilities of children with autism spectrum disorder (ASD), who exhibit delays and/or deviations in attaining similar milestones. This project approaches this question by studying gesture and speech use at two crucial milestones of language development, namely onset of sentences to request and comment (study 1) and onset of extended speech in narratives and explanations (study 2) using longitudinal observations. Study 1, focusing on first sentences, examines changes in gestures and speech of 18 children with ASD and 18 typically developing children, as they transition from producing single words to simple sentences in two language contexts: commenting on objects and requesting objects. Study 2, focusing on extended speech, examines changes in gestures and speech of 25 children with ASD and 25 typically developing children in two language contexts: producing narratives and providing explanations. Given the reported difficulties children with ASD exhibit in gesture production at the early ages--followed by delays in later speech production--the project asks whether the pattern of gesture-speech combinations leading the way to early sentences and later narratives/explanations is disrupted, or whether this language-learning process is so robust that children with ASD, like typically developing children, initially rely on gesture and speech together to convey their emerging spoken language abilities.This research will make an important contribution in two major respects: First, the findings will inform theories of language development about the robustness of the gesture-speech system across different learners. Compared to typically developing children, the language-learning trajectory of children with ASD shows variability, with weaknesses in early commenting and later narrative contexts, accompanied by relative strengths in early requesting and later explanation contexts. Children with ASD also show unique deficits in early pointing gestures, but relative strengths in later iconic gestures, making them an ideal group to understand whether and how gesture is part of the developmental process that supports language-learning across stages and contexts of language acquisition. Second, the findings have potential clinical implications. Gesture, when considered in relation to the accompanying speech, can be used to identify when a child is in a transitional state with respect to a language milestone. More specifically, children whose gestures convey different information from their speech show more readiness to learn, and in turn, are also more likely to benefit from instruction. As such, gestures might serve as a good index of emerging language abilities, which, in turn, may help educators and clinicians to identify the best time to introduce task-specific strategies for language learning for children whose development is delayed or deviant. These strategies could range from providing more targeted spoken language input to explicitly encouraging children to use particular gestures when talking about the concepts that they are at the cusp of learning--both of which have been shown to be effective strategies in teaching new concepts to typically developing children.