Effects of Recast Rate and Distribution on Irregular Past Tense Acquisition

描述（由申请人提供）：特殊语言障碍儿童（SLI）在语法发展方面落后于典型语言发展儿童（TL），尽管他们在早期同样接触到成人在对话中进行语法纠正的形式，称为重铸（Fey等人，1999），并且他们在干预中表现出的从重铸中学习的能力与TL儿童一样快（Nelson等人，1996）。重铸是成人对儿童话语的直接反应，重复儿童的一些词语，纠正或以其他方式修改儿童先前话语的形态或句法形式，同时保持儿童话语的中心意义。例如，如果一个孩子说“它掉下来了”，一个成年人的矫正铸模就会是“它掉下来了”。从一个理论角度来看，特殊语言障碍儿童的语法问题的基础涉及工作记忆、处理速度和容量的限制（Leonard et al., 2007）。Leonard等人认为，减少处理需求和多次重复单词和句子的干预方法有可能超越处理限制。重铸的促进特性及其在治疗中使用的灵活性使它们能够满足这些条件。然而，问题仍然存在，临床医生如何在干预中最有效地使用重铸？Warren等人（2007）认为，儿童语言领域是时候开始专门研究治疗强度的组成部分，如剂量，以及它们对治疗效果的影响。目前，这样的研究几乎不存在。拟议的研究将开始填补这一空白，通过检查两个具体方面的剂量：重铸率和重铸分布。本研究的具体目的是确定重投的频率和分布如何影响24名患有特殊语言障碍的儿童（4岁和5岁）和24名更小的语言相当的患有特殊语言障碍的儿童（3岁）对新动词不规则过去时的习得。本研究采用多因素组间设计，包括两个独立的实验任务。实验1考察了儿童在五次实验中，以0.5/min、1.0/min和1.5/min三种重放速率中的一种来学习两个不规则过去时态的新动词（dake-doke和kig-kug）。实验2考察了儿童在1、2、5个实验阶段中分别接受20次动词接触，并对两种不同的不规则过去时新动词（jare-jore和twink-twank）的习得情况。结果变量包括在会话期间和测试后探针中目标动词的强制性上下文中准确生成的百分比。本研究计划代表了有三个长期目标的研究路径中的第四项研究：(1)建立有效的早期干预技术，这将有助于改善SLI的长期人际和学业后果；(2)详细了解影响特殊语言障碍儿童形态句法习得的语言加工限制；(3)建立一套区分晚语儿童与语言障碍儿童的动态评估方案。本研究的方法和结果将对未来的随机临床试验有重要贡献。该项目将为一种广泛使用的干预方法提供具体的剂量信息，即句子重铸，它有助于具有典型语言发育的儿童（cf. Farrar, 1992）和具有特殊语言障碍的儿童（cf. Nelson, Camarata, Welsh, Butovsky & Camarata, 1996）的语法发展。确定有效的重塑剂量参数可能是对特殊语言障碍儿童进行一致、有效的干预结果的关键（Warren, Fey & Yoder, 2007）。在有特殊语言障碍的儿童中，考虑到这一群体所表现出的长期人际关系（参见Kaiser， Cai, Hancock, & Foster, 2002）和学术困难（参见Catts & Kamhi， 1999）以及相关的社会成本，快速和早期的语法技能提高到与正常发展的同龄人相近的水平将会带来显著的好处（Fey & Proctor-Williams, 2000）。

DESCRIPTION (provided by applicant): Children with specific language impairment (SLI) lag behind children with typical language development (TL) in their grammatical development, despite equivalent early exposures to a form of adult grammatical corrections in conversation, called recasts (Fey et al., 1999), and their demonstrated ability to learn from recasts in intervention as quickly as do children with TL (Nelson et al., 1996). Recasts are immediate adult responses to child utterances that repeat some of the child's words and correct or otherwise modify the morphologic or syntactic form of the child's prior utterance, while maintaining the central meaning of the child's production. For example, if a child said "It falled down", an adult corrective recast would be "It fell down". From one theoretical view, the basis of the grammatical problems of children with SLI involves limitations in working memory, and processing speed and capacity (Leonard et al., 2007). Leonard et al. suggest that intervention approaches that decrease processing demands and offer multiple repetitions of words and sentences have the potential to override processing limitations. The facilitative properties of recasts and the flexibility of their use in treatment give them the capability to fulfill these conditions. The question remains, however, how can clinicians employ recasts in intervention most efficaciously? Warren et al. (2007) suggest that it is time for the field of child language to begin specifically investigating components of treatment intensiveness, such as dosage, and their impact on treatment efficacy. Currently, such research is virtually nonexistent. The proposed study will begin to fill this gap through examination of two specific aspects of dosage: recast rate and recast distribution. The specific aim of this study is to determine how rate and distribution of recasts affects acquisition of irregular past tense of novel verbs, by 24 children with SLI (4- and 5-yr olds) and 24 younger, language equivalent children with TL (3-yr olds). This study, which utilizes a multifactor between groups design, includes two independent experimental tasks. Experiment 1 examines the children's learning of two irregular past tense novel verbs (dake-doke and kig-kug) in response to one of three rates of recasts, 0.5/min, 1.0/min, or 1.5/min, over five sessions. Experiment 2 examines the children's acquisition of two different irregular past tense novel verbs (jare-jore and twink-twank) when given 20 verb exposures each in 1, 2 or 5 sessions. Outcome variables include percent of accurate production in obligatory contexts of the target verbs during the sessions and on post-test probes. This research proposal represents the fourth study in a path of research that has three long- term goals: (1) establishment of efficacious early intervention techniques that will contribute to the amelioration of the long-term interpersonal and academic consequences of SLI; (2) a detailed understanding of language processing limitations that affect morphosyntactic acquisition of children with SLI; and (3) development of a dynamic assessment protocol that distinguishes late-talking toddlers with SLI from those with TL. The methodology and results of the proposed study will contribute significantly to future randomized clinical trials. PUBLIC HEALTH RELEVANCE This project will offer specific information about dosage for a widely-used intervention approach, sentence recasting, which facilitates the grammatical development of children with typical language development (cf. Farrar, 1992) and those with specific language impairment (cf. Nelson, Camarata, Welsh, Butovsky & Camarata, 1996). Identification of effective recast dosage parameters might prove to be the key to consistent, effective, intervention outcomes for children with specific language impairment (Warren, Fey & Yoder, 2007). In children with specific language impairment, rapid and early improvement in grammar skills to levels that approximate those of their typically developing peers would be of significant benefit, (Fey & Proctor-Williams, 2000) given the demonstrated long-term interpersonal (cf. Kaiser, Cai, Hancock, & Foster, 2002), and academic difficulties (cf. Catts & Kamhi, 1999) of this population and the associated costs to society.