Context-Dependent Learning of Linguistic Disjunction.

What are the constraints, cues, and mechanisms that help learners create successful word-meaning mappings? This study takes up linguistic disjunction and looks at cues and mechanisms that can help children learn the meaning of or. We first used a large corpus of parent-child interactions to collect statistics on or uses. Children started producing or between 18-30 months and by 42 months, their rate of production reached a plateau. Second, we annotated for the interpretation of disjunction in child-directed speech. Parents used or mostly as exclusive disjunction, typically accompanied by rise-fall intonation and logically inconsistent disjuncts. But when these two cues were absent, disjunction was generally not exclusive. Our computational modeling suggests that an ideal learner could successfully interpret an English disjunction (as exclusive or not) by mapping forms to meanings after partitioning the input according to the intonational and logical cues available in child-directed speech.

Exposure and feedback in language acquisition: adult construals of children's early verb-form use in Hebrew.

This study focuses on adult responses to children's verb uses, the information they provide, and how they change over time. We analyzed longitudinal samples from four children acquiring Hebrew (age-range: 1;4-2;5; child verb-forms = 8,337). All child verbs were coded for inflectional category, and for whether and how adults responded to them. Our findings show that: (a) children's early verbs were opaque with no clear inflectional target (e.g., the child-form tapes corresponds to letapes 'to-climb', metapes 'is-climbing', yetapes 'will-climb'), with inflections added gradually; (b) most early verbs were followed by adult responses using the same lexeme; and (c) as opacity in children's verbs decreased, adults made fewer uses of the same lexeme in their responses, and produced a broader array of inflections and inflectional shifts. In short, adults are attuned to what their children know and respond to their early productions accordingly, with extensive 'tailor-made' feedback on their verb uses.

"The moustache sits down first": on the acquisition of metonymy.

This study investigates preschoolers' ability to understand and produce novel metonyms. We gave forty-seven children (aged 2;9-5;9) and twenty-seven adults one comprehension task and two elicitation tasks. The first elicitation task investigated their ability to use metonyms as referential shorthands, and the second their willingness to name animates metonymically on the basis of a salient property. Although children were outperformed by adults, even three-year-olds could understand and produce metonyms in certain circumstances. Our results suggest that young children may find it easier to produce a metonym than a more elaborate referential description in certain contexts, and that metonymy may serve as a useful strategy in referring to entities that lack a conventional label. However, metonymy comprehension appeared to decrease with age, with older children tending to choose literal interpretations of some metonyms. This could be a result of growing metalinguistic awareness, which leads children to overemphasize literal meanings.

Pragmatic inferences in context: learning to interpret contrastive prosody.

Can preschoolers make pragmatic inferences based on the intonation of an utterance? Previous work has found that young children appear to ignore intonational meanings and come to understand contrastive intonation contours only after age six. We show that four-year-olds succeed in interpreting an English utterance, such as "It LOOKS like a zebra", to derive a conversational implicature, namely [but it isn't one], as long as they can access a semantically stronger alternative, in this case "It's a zebra". We propose that children arrive at the implicature by comparing such contextually provided alternatives. Contextually leveraged inferences generalize across speakers and contexts, and thus drive the acquisition of intonational meanings. Our findings show that four-year-olds and adults are able to bootstrap their interpretation of the contrast-marking intonation by taking into account alternative utterances produced in the same context.

Early verb constructions in French: adjacency on the left edge.

Children acquiring French elaborate their early verb constructions by adding adjacent morphemes incrementally at the left edge of core verbs. This hypothesis was tested with 2657 verb uses from four children between 1;3 and 2;7. Consistent with the Adjacency Hypothesis, children added clitic subjects first only to present tense forms (as in il saute 'he jumps'); modals to infinitives (as in faut sauter 'has to jump'); and auxiliaries to past participles (as in a sauté 'has jumped'). Only after this did the children add subjects to the left of a modal or auxiliary, as in elle veut sauter 'she wants to jump', or elle a sauté 'she has jumped'. The order in which these elements were added, and the development in the frequencies of the constructions, all support the predictions of the Adjacency Hypothesis for left edge development in early verb constructions.

Turn-taking, timing, and planning in early language acquisition.

Young children answer questions with longer delays than adults do, and they don't reach typical adult response times until several years later. We hypothesized that this prolonged pattern of delay in children's timing results from competing demands: to give an answer, children must understand a question while simultaneously planning and initiating their response. Even as children get older and more efficient in this process, the demands on them increase because their verbal responses become more complex. We analyzed conversational question-answer sequences between caregivers and their children from ages 1;8 to 3;5, finding that children (1) initiate simple answers more quickly than complex ones, (2) initiate simple answers quickly from an early age, and (3) initiate complex answers more quickly as they grow older. Our results suggest that children aim to respond quickly from the start, improving on earlier-acquired answer types while they begin to practice later-acquired, slower ones.

Turn-taking: a case study of early gesture and word use in answering WHERE and WHICH questions.

When young children answer questions, they do so more slowly than adults and appear to have difficulty finding the appropriate words. Because children leave gaps before they respond, it is possible that they could answer faster with gestures than with words. In this study, we compare gestural and verbal responses from one child between the ages of 1;4 and 3;5, to adult Where and Which questions, which can be answered with gestures and/or words. After extracting all adult Where and Which questions and child answers from longitudinal videotaped sessions, we examined the timing from the end of each question to the start of the response, and compared the timing for gestures and words. Child responses could take the form of a gesture or word(s); the latter could be words repeated from the adult question or new words retrieved by the child. Or responses could be complex: a gesture + word repeat, gesture + new word, or word repeat + new word. Gestures were the fastest overall, followed successively by word-repeats, then new-word responses. This ordering, with gestures ahead of words, suggests that the child knows what to answer but needs more time to retrieve any relevant words. In short, word retrieval and articulation appear to be bottlenecks in the timing of responses: both add to the planning required in answering a question.

Pragmatics in acquisition.

Recent research has highlighted several areas where pragmatics plays a central role in the process of acquiring a first language. In talking with their children, adults display their uses of language in each context, and offer extensive feedback on form, meaning, and usage, within their conversational exchanges. These interactions depend critically on joint attention, physical co-presence, and conversational co-presence - essential factors that help children assign meanings, establish reference, and add to common ground. For young children, getting their meaning across also depends on realizing language is conventional, that words contrast in meaning, and that they need to observe Grice's cooperative principle in conversation. Adults make use of the same pragmatic principles as they solicit repairs to what children say, and thereby offer feedback on both what the language is and how to use it.

Repetition as ratification: how parents and children place information in common ground.

Repetition is used for a range of functions in conversation. In this study, we examined all the repetitions used in spontaneous conversations by 41 French adult-child dyads, with children aged 2 ; 3 and 3 ; 6, to test the hypotheses that adults repeat to establish that they have understood, and that children repeat to ratify what adults have said. Analysis of 978 exchanges containing repetitions showed that adults use them to check on intentions and to correct errors, while children use them to ratify what the adult said. With younger children, adults combine their repeats with new information. Children then re-repeat the form originally targeted by the adult. With older children, adults check on intentions but less frequently, and only occasionally check on forms. Older children also re-repeat in the third turn but, like adults, add further information. For both adults and children, repeats signal attention to the other's utterances, and place the information repeated in common ground.

Getting and maintaining attention in talk to young children.

When two people talk about an object, they depend on joint attention, a prerequisite for setting up common ground in a conversational exchange. In this study, we analyze this process for parent and child, with data from 40 dyads, to show how adults initiate joint attention in talking to young children (mean ages 1;6 and 3;0). Adults first get their children's attention with a summons (e.g. Ready?, See this?), but cease using such forms once children give evidence of attending. Children signal their attention by looking at the target object, evidence used by the adults. Only at that point do adults begin to talk about the object. From then on, they use language and gesture to offer information about and maintain attention on the target. The techniques adults rely on are interactive: they establish joint attention and maintain it throughout the exchange.

Color, reference, and expertise in language acquisition.

In learning the meaning of a new term, children need to fix its reference, learn its conventional meaning, and discover the meanings with which it contrasts. To do this, children must attend to adult speakers--the experts--and to their patterns of use. In the domain of color, children need to identify color terms as such, fix the reference of each one, and learn how each is used in the language. But color is a property, and terms for properties appear to be more difficult to grasp than do those for objects, actions, and relations. Although children find some domains easier to learn than others, they depend in each case on the expertise of adult speakers.

How language acquisition builds on cognitive development.

When children acquire a first language, they build on what they know--conceptual information that discriminates and helps create categories for the objects, relations and events they experience. This provides the starting point for language from the age of 12 months on. So children first set up conceptual representations, then add linguistic representations for talking about experience. Do they then discard earlier conceptual representations in favour of linguistic ones, or do they retain them? Recent research on the coping strategies that young children (and adults) rely on when they are unable to draw on language suggest that they retain both types of representations for use as needed.

Adult reformulations of child errors as negative evidence.

Parents frequently check up on what their children mean. They often do this by reformulating with a side sequence or an embedded correction what they think their children said. These reformulations effectively provide children with the conventional form for that meaning. Since the child's utterance and the adult reformulation differ while the intended meanings are the same, children infer that adults are offering a correction. In this way, reformulations identify the locus of any error, and hence the error itself. Analyses of longitudinal data from five children between 2;0 and 4;0 (three acquiring English and two acquiring French) show that (a) adults reformulate their children's erroneous utterances and do so significantly more often than they replay or repeat error-free utterances; (b) their rates of reformulation are similar across error-types (phonological, morphological, lexical, and syntactic) in both languages; (c) they reformulate significantly more often to younger children, who make more errors. Evidence that children attend to reformulations comes from four measures: (a) their explicit repeats of corrected elements in their next turn; (b) their acknowledgements (yeah or uh-huh) as a preface to their next turn; (c) repeats of any new information included in the reformulation; and (d) their explicit rejections of reformulations where the adult has misunderstood. Adult reformulations, then, offer children an important source of information about how to correct errors in the course of acquisition.