It has long been claimed that the child’s experience of language is not sufficient to enable them to learn language, and so language structure must be innate and internal to the child. However, this traditional view depends on considering the child’s experience of language only in terms of the sequences of words that children hear. Yet, the language environment is rich, multimodal, noisy, and stimulating, going far beyond mere sequences of words. In this work package we investigated which sources of information in the child’s environment are available to support learning to identify words, determine their meaning, and their grammatical role in sentences. We also explored the contemporary influence of new media in adapting children’s experience of this language environment. Using a combination of computational modelling, corpus analysis of child-directed speech, experimental studies, and survey methods, we discovered that: The arrangement of sounds in words, the distribution of words in speech, the gesture of caregivers, and the presence and absence of objects and events around children each contributed to promote early stages of language learning. Combinations of cues were even more powerful in supporting learning than individual cues, and when these cues were variable, or noisy, this was optimal for language learning. Children’s ability to identify words in artificial speech related to their vocabulary development in the first two years of life, and the cues they relied on to identify words were the same as those used to identify the grammatical role of words in the language. At the point when language learners acquire their first words, they are already sensitive to the grammatical role of those words: vocabulary and grammar appear to be acquired simultaneously and early in language development. Use of new media (e.g., smartphones) is substantial in children’s preschool years, but children’s early language development was best predicted by their time spent co-reading with their caregivers, rather than the time spent on new media devices. Experimental studies: Study 1 with adults on whether intervening high-frequency function words can support segmentation of speech and contribute to categorisation of syntactic categories in language learning. Study 2 with infants testing whether intervening high-frequency function words support segmentation and syntax learning. Study 3 with infants testing whether children can segment and generalise structure of language at the same time from continuous artificial speech input. Study 6 with adults testing whether probabilistic multiple cues can support word-referent mappings. Study 7 with infants testing whether probabilistic multiple cues can support word-referent mappings. Study 8 with adults testing effect of sleep on learning to segment artificial speech and learning to generalise grammatical structure from the same speech. Study 9 Simultaneous segmentation and generalisation of non-adjacent dependencies from continuous speech. Study 10 with adults testing how referents for nouns and verbs can be learned under different instruction conditions. Study 11 with adults testing how referents for nouns, verbs, adjectives, and grammatical role marker words, and syntax, can be learned under different instruction conditions. Questionnaire study: Study 12: Questionnaire on children’s media use and relation to expressive and productive vocabulary. Meta-analysis review study: Study 5: Meta-analysis of studies testing conditions of learning of different grammatical structures across species. Computational modelling: Study 4: Computational model testing whether probabilistic multiple cues can support word-referent mappings.The International Centre for Language and Communicative Development (LuCiD) will bring about a transformation in our understanding of how children learn to communicate, and deliver the crucial information needed to design effective interventions in child healthcare, communicative development and early years education. Learning to use language to communicate is hugely important for society. Failure to develop language and communication skills at the right age is a major predictor of educational and social inequality in later life. To tackle this problem, we need to know the answers to a number of questions: How do children learn language from what they see and hear? What do measures of children's brain activity tell us about what they know? and How do differences between children and differences in their environments affect how children learn to talk? Answering these questions is a major challenge for researchers. LuCiD will bring together researchers from a wide range of different backgrounds to address this challenge. The LuCiD Centre will be based in the North West of England and will coordinate five streams of research in the UK and abroad. It will use multiple methods to address central issues, create new technology products, and communicate evidence-based information directly to other researchers and to parents, practitioners and policy-makers. LuCiD's RESEARCH AGENDA will address four key questions in language and communicative development: 1. ENVIRONMENT: How do children combine the different kinds of information that they see and hear to learn language? 2. KNOWLEDGE: How do children learn the word meanings and grammatical categories of their language? 3. COMMUNICATION: How do children learn to use their language to communicate effectively? 4. VARIATION: How do children learn languages with different structures and in different cultural environments? The fifth stream, the LANGUAGE 0-5 PROJECT, will connect the other four streams. It will follow 80 English learning children from 6 months to 5 years, studying how and why some children's language development is different from others. A key feature of this project is that the children will take part in studies within the other four streams. This will enable us to build a complete picture of language development from the very beginning through to school readiness. Applying different methods to study children's language development will constrain the types of explanations that can be proposed, helping us create much more accurate theories of language development. We will observe and record children in natural interaction as well as studying their language in more controlled experiments, using behavioural measures and correlations with brain activity (EEG). Transcripts of children's language and interaction will be analysed and used to model how these two are related using powerful computer algorithms. LuciD's TECHNOLOGY AGENDA will develop new multi-method approaches and create new technology products for researchers, healthcare and education professionals. We will build a 'big data' management and sharing system to make all our data freely available; create a toolkit of software (LANGUAGE RESEARCHER'S TOOLKIT) so that researchers can analyse speech more easily and more accurately; and develop a smartphone app (the BABYTALK APP) that will allow parents, researchers and practitioners to monitor, assess and promote children's language development. With the help of six IMPACT CHAMPIONS, LuCiD's COMMUNICATIONS AGENDA will ensure that parents know how they can best help their children learn to talk, and give healthcare and education professionals and policy-makers the information they need to create intervention programmes that are firmly rooted in the latest research findings.

Opportunity sample.