Lexicon development in bilingual toddler

双语，而不是单语，是全球的规范（教科文组织，2003年）。我们很好地理解了成年双语者的大脑是如何储存两种语言中的单词的：例如，我们知道，一个精通法语和英语的双语者，当听到英语单词“dog”时，会无意识地抑制它的法语对应词“chien”。然而，很少有人知道这些词是如何在一个年轻的双语者的头脑中组织的。这不是一个小问题，因为即使是单语儿童对单词的心理处理也与成人不同。了解双语儿童如何处理词汇对评估他们的语言学习能力具有重要意义。双语者在语言发展的关键阶段往往会出现延迟，这可能导致过度推荐言语和语言治疗。相反的问题也很普遍，转诊不足的基础上，一些延迟，相对于单语，预计。评估系统中的这些缺陷在短期和长期内都会给社会带来代价，因为一个有语言问题而未被发现的孩子将在学业和社交方面陷入困境。缺乏双语语言评估工具可以归因于（1）缺乏对双语词汇发展结构的了解（2）社会和语言对双语语言发展的多重影响，这两个问题，特别是它们的组合，我们知之甚少。例如，我们知道正在学习的语言之间的语言距离是非常重要的，但是我们没有工具来测量儿童的语言距离。在这里，我们提出了一个新的基于计算机的双语词汇发展模型，基于实验数据，这将提供（1）我们对双语的理论理解的重大进展，及（二）为发展一套评估青少年双语能力发展的通用工具铺路。这项计划分为三个阶段：两个为期三年的资料搜集阶段及一个最后一年的模型阶段。孩子将在18个月大，这通常标志着词汇发展的急剧增长。在第一个数据收集流中，我们将进行一系列实验，检查双语婴儿的单词组织。与牛津婴儿实验室合作，将介绍意义相关或不相关的口语单词对（“chien”-“猪”或“chien”-“船”），并配以适当的图片。儿童寻找相关图片和不相关图片的时间将告诉我们单词之间联系的强度。在第二个数据收集流中，我们的目标是测量影响双语者词汇发展的外部因素之间的相互作用。250名双语幼儿将在英国的五个不同地点（普利茅斯、班戈尔、伯明翰、肯特和利物浦）接受评估，以获得语言背景和社会经济地位方面的大量细节。婴儿接触两种语言的数量和方式将通过适当的问卷调查进行检查。他们的英语词汇水平和其他语言将通过语言特定的MacArthur-Bates沟通发展清单（CDI）进行评估，词汇问卷有60种语言版本。来自CDIs的数据将帮助我们设计儿童调整的两种语言学习距离的指标。在最后的建模流程中，之前数据收集流程的结果将用于创建双语词汇发展的计算模型，该模型将能够预测幼儿在不同社会和语言环境中的语言发展。该项目将大大推进我们对年轻双语者语言处理的理解，并为为目前被忽视的这一群体设计通用语言评估工具奠定基础。

Bilingualism, not monolingualism, is the global norm (UNESCO, 2003). We have a good understanding of how the minds of adult bilinguals store words in their two languages: for example, we know that a proficient French-English bilingual, when hearing the English word 'dog', unconsciously inhibits its French equivalent, 'chien'. However, there is little known about how the words are organised in the mind of a young bilingual. This is not a trivial problem as even monolingual children's mental processing of words is different from that of adults. Understanding how bilingual children deal with words has important implications for assessment of their language learning abilities. Bilinguals tend to have delays in critical stages of language development, which can lead to over-referral for Speech and Language Therapy. The opposite problem is also prevalent, under-referral on the basis that some delay, relative to monolinguals, is expected. Such failings in the assessment system are costly for society in the short-term and the long-term, as a child with undetected language problems will struggle academically and socially.The absence of bilingual-specific tools for language assessment can be attributed to (1) lack of knowledge about the architecture of the developing bilingual lexicon (2) the multiple social and linguistic influences on bilingual language development, which are poorly understood, particularly in combination. For example, we know that the linguistic distance between the languages being learnt is very important, but we don't have tools to measure linguistic distance in children.Here we propose to produce a new computer-based model of the developing bilingual lexicon, based on experimental data, that will provide (1) significant advances in our theoretical understanding of bilingualism, and (2) pave the road for the development of a universal tool for the assessment of young bilinguals' language development.This project is organised in three streams: two three-year data-collection streams and a final-year modelling stream. Children will be aged 18 months, which usually marks the onset of a sharp increase in vocabulary development.In the first data-collection stream, we will run a series of experiments examining the organisation of words in bilingual infants. In collaboration with the Oxford Babylab, pairs of spoken words related or unrelated in meaning ('chien'-'pig' or 'chien'-'boat') will be presented accompanied by appropriate pictures. Children's looking times for pictures associated with related versus unrelated pairs will inform us about the strength of connections between words.In the second data-collection stream, we aim to measure the interactions between the external factors influencing vocabulary development in bilinguals. Two hundred and fifty bilingual toddlers will be assessed in five different sites in the UK (Plymouth, Bangor, Birmingham, Kent and Liverpool) to get a large range of specifics in terms of language background and socioeconomic status. Infants' amount and mode of exposure to their two languages will be checked through appropriate questionnaires. Their level of vocabulary in English and the additional language will be evaluated through language-specific MacArthur-Bates Communicative Development Inventories (CDI), vocabulary questionnaires with versions for 60 languages. The data from the CDIs will help us to design child-adjusted metrics of distance between the two languages being learned. In the final, modelling stream, the findings from the previous data-collection streams will be used to create a computational model of bilingual lexicon development, which will be able to predict language development in toddlers in different social and linguistic environments.This project will considerably advance our understanding of language processing in young bilinguals, and prepare the ground for the design of a universal language assessment tool for this currently overlooked population.