Lexicon development in bilingual toddler

双语而不是单一语言是全球规范(教科文组织，2003)。我们对成年双语者的大脑如何在他们的两种语言中存储单词有很好的理解：例如，我们知道一个熟练的法英双语者，当听到英语单词Dog时，会下意识地抑制与其对应的法语单词Chien。然而，关于这些词是如何在年轻的双语者的脑海中组织起来的，我们知之甚少。这不是一个微不足道的问题，因为即使是只会说一种语言的儿童对单词的心理加工也不同于成年人。了解双语儿童如何处理单词，对于评估他们的语言学习能力具有重要的意义。双语者往往在语言发展的关键阶段有延误，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，转诊不足的理由是，相对于只会说一种语言的人，预计会有一些延误。评估系统中的这种缺陷在短期和长期都会给社会带来代价，因为有未被发现的语言问题的儿童将在学业和社交方面遇到困难。缺乏专门针对双语的语言评估工具可归因于：(1)缺乏对正在发展的双语词汇体系的了解；(2)社会和语言对双语发展的多重影响，人们对这些影响知之甚少，特别是结合在一起。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，但我们没有工具来衡量儿童的语言距离。在这里，我们建议基于实验数据建立一个新的基于计算机的双语词汇发展模型，它将提供(1)在我们对双语的理论理解方面的重大进展，以及(2)为开发一个评估年轻双语者语言发展的通用工具铺平道路。该项目分三个流组织：两个为期三年的数据收集流和最后一年的模型流。18个月的儿童通常标志着词汇发展的急剧增加。在第一个数据收集流中，我们将进行一系列实验，研究双语婴儿的词汇组织。在与牛津婴儿实验室的合作下，词义相关或无关的口语单词对(‘钱’-‘猪’或‘钱’-‘船’)将伴随着适当的图片呈现。在第二个数据收集流程中，我们旨在测量影响双语者词汇发展的外部因素之间的交互作用。250名双语幼儿将在英国五个不同的地点(普利茅斯、班戈、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广泛细节。将通过适当的问卷调查婴儿接触两种语言的数量和方式。他们的英语和额外语言的词汇水平将通过特定语言的麦克阿瑟-贝茨交际发展量表(CDI)进行评估，这是一份包含60种语言版本的词汇问卷。来自CDI的数据将帮助我们设计儿童调整的两种正在学习的语言之间的距离度量标准。在最后的模型流中，来自先前数据收集流的结果将被用来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。该项目将极大地促进我们对年轻双语者语言加工的理解，并为为这一目前被忽视的人群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.