The past and present state of the empiricism–nativism issue is analysed. Empiricist philosophical doctrine (‘no innate ideas’) distinguished idea from structure or mechanism. However, Chomsky's conception of innate linguistic universals erased this distinction. The elimination left would-be empiricists without a coherent and defensible position. I argue that the issue remains alive primarily because of tension between two scientific tasks that face students of development. One is to discover what is cognitively and linguistically primitive, a task that encourages nativism. However, nativism is ultimately unsatisfactory because it systematically neglects the other task, which is to account for development, including the emergence of postulated innate primitives. To account for such primitives, it is necessary to relate them to particular central nervous System structures in such a way as to explain how the structure has the particular cognitive effects that define the primitive. That is likely to be difficult, and I show how the study of learning – much neglected in recent years – can help by reducing the number and type of innate primitives whose origin must be explained in that way.

This work reports longitudinal evaluation of the speech-like vocal development of infants born at risk due to prematurity or low socio-economic status (SES) and infants not subject to such risk. Twenty infants were preterm (10 of low SES) and 33 were full term (16 of low SES), and all were studied from 0;4 through 1;6. The study provides the indication that at-risk infants are not generally delayed in the ability to produce well-formed speech-like sounds as indicated in taperecorded vocal samples. At the same time, premature infants show a tendency to produce well-formed syllables less consistently than full terms after the point at which parents and laboratory personnel note the onset of the canonical babbling stage (the point after which well-formed syllables are well established in the infant vocal repertoires). Further, even though low SES infants produce well-formed speech-like structures on schedule, they show a reliably lower tendency to vocalize in general, as reflected by fewer utterances per minute in recorded samples.

In this study it is argued that the omission of closed class morphemes and of unstressed syllables within words is related to their common characteristic, viz. that they are unstressed, rhythmically weak parts of utterances. Several strands of evidence indicate that it is unlikely that children are unable to perceive these elements in the input speech. The pattern of (non)realization of unstressed syllables within content words and the class of determiners, was analysed in two Dutch children from 1;6 to 2;11. It appeared that polysyllabic words were quite generally truncated in such a way that they fitted a trochaic (strong-weak) pattern, particularly in the early samples. Some observations with respect to the (non)realization of determiners are suggestive of an influence of an SW-constraint on the realization of noun phrases. These findings support the hypothesis that in the course of utterance preparation, words and phrases are mapped onto S(W) templates. Anecdotal evidence suggests that the dissolution of the SW-constraint coincides with the acquisition of specific aspects of stress assignment in Dutch, such as quantity sensitivity.

Results are reported for stylistic and developmental aspects of vocabulary composition for 1, 803 children and families who participated in the tri-city norming of a new parental report instrument, the MacArthur Communicative Development Inventories. We replicate previous studies with small samples showing extensive variation in use of common nouns between age o;8 and 1;4 (i.e. ‘referential style’), and in the proportion of vocabulary made up of closed-class words between 1;4 and 2;6 (i.e. ‘analytic’ vs. ‘holistic’ style). However, both style dimensions are confounded with developmental changes in the composition of the lexicon, including three ‘waves’ of reorganization: (1) an initial increase in percentage of common nouns from 0 to 100 words, followed by a proportional decrease; (2) a slow linear increase in verbs and other predicates, with the greatest gains taking place between 100 and 400 words; (3) no proportional development at all in the use of closed-class vocabulary between 0 and 400 words, followed by a sharp increase from 400 to 680 words. When developmental changes in noun use are controlled, referential-style measures do not show the association with developmental precocity reported in previous studies, although these scores are related to maternal education. By contrast, when developmental changes in grammatical function word use are controlled, high closed-class scores are associated with a slower rate of development. We suggest that younger children may have less perceptual acuity and/or shorter memory spans than older children with the same vocabulary size. As a result, the younger children may ignore unstressed function words until a later point in development while the older children tend to reproduce perceptual details that they do not yet understand. Longitudinal data show that early use of function words (under 400 words) is not related to grammatical levels after the 4OO-word point, confirming our ‘stylistic’ interpretation of early closed-class usage. We close with recommendations for the unconfounding of stylistic and developmental variance in research on individual differences in language development, and provide look-up tables that will permit other investigators to pull these aspects apart.

Universally, object names make up the largest proportion of any word type found in children's early lexicons. Here we present and critically evaluate a set of six lexical principles (some previously proposed and some new) for making object label learning a manageable task. Overall, the principles have the effect of reducing the amount of information that language-learning children must consider for what a new word might mean. These principles are constructed by children in a two-tiered developmental sequence, as a function of their sensitivity to linguistic input, contextual information, and social-interactional cues. Thus, the process of lexical acquisition changes as a result of the particular principles a given child has at his or her disposal. For children who have only the principles of the first tier (REFERENCE, EXTENDIBILITY, and OBJECT SCOPE), word learning has a deliberate and laborious look. The principles of the second tier (CATEGORICAL SCOPE, NOVEL NAME – NAMELESS CATEGORY’ or N3C, and CONVENTIONALITY) enable the child to acquire many new labels rapidly. The present unified account is argued to have a number of advantages over treating such principles separately and non-developmentally. Further, the explicit recognition that the acquisition and operation of these principles is influenced by the child's interpretation of both linguistic and non-linguistic input is seen as an advance.

Pronoun case errors, or overextensions, like *me want it are characteristic of English child language. This paper explores a hypothesis that the morphological structure of a pronoun influences the pattern of these errors. The Language Acquisition Device (LAD) attempts to analyse English pronoun case forms into stems and affixes, but cannot because of their irregularity. Nevertheless the LAD extracts a phonetic core for each pronoun (e.g. /m-/ for the ist sg., /h-/ for the 3rd masc. sg.). The phonetic core blocks the overextension of suppletive nominative forms like I and she. This hypothesis predicts strong differences in the frequency and types of errors between pronouns with suppletive nominatives and those without. Evidence for this hypothesis was found in a transcript database of twelve children, with data collected in one hour samples every month from 1;0 to 3;0. 20,908 pronouns were examined, 1347 of which were errors. Statistical analyses of these data provide support for this hypothesis.

What is the input to the mental System that computes inflected forms like walked, came, dogs, and men? Recent connectionist models feed a word's phonological features into a single network, allowing it to generalize both regular and irregular phonological patterns, like stop-stopped, step-stepped and fling-flung, cling-clung. But for adults, phonological input is insufficient: verbs derived from nouns like ring the city always have regular past tense forms (ringed), even if they are phonologically identical to irregular verbs (ring the bell). Similarly, nouns based on names, like two Mickey Mouses, and compounds based on possessing rather than being their root morpheme, such as two sabertooths, take regular plurals, even when they are homophonous with irregular nouns like mice and teeth. In four experiments, testing 70 three- to ten-year-old children, we found that children are sensitive to such nonphonological information: they were more likely to produce regular inflected forms for forms like to ring (‘to put a ring on’) and snaggletooth (a kind of animal doll with big teeth) than for their homophonous irregular counterparts, even when these counterparts were also extended in meaning. Children's inflectional Systems thus seem to be like adults': irregular forms are tied to the lexicon but regular forms are computed by a default rule, and words are represented as morphological tree structures reflecting their derivation from basic word roots. Such structures, which determine how novel complex words are derived and interpreted, also govern whether words with irregular sound patterns will be regularized: a word can be irregular only if its structure contains an irregular root in ‘head’ position, allowing the lexically stored irregular information to percolate up to apply to the word as a whole. In all other cases, the inflected form is computed by a default regular rule. This proposal fits the facts better than alternatives appealing to ambiguity reduction or semantic similarity to a word's central sense. The results, together with an analysis of adult speech to children, suggest that morphological structure and a distinction between mechanisms for regular and irregular inflection may be inherent to the design of children's language Systems.

The purpose of this article is to provide a contemporary Government-and-Binding (GB) reinterpretation and evaluation of Klima & Bellugi's classic 1966 work on the acquisition of interrogatives. I argue that the central insight of K&B's paper can be captured by positing that wh- questions in Child English involve a wh-pronoun positioned in the head complementizer (C) position within the Complementizer Phrase (CP) (so blocking auxiliary inversion if this involves positioning an inverted auxiliary in C) and that in the transition to Adult English, children come to learn that wh-questions involve a wh-phrase superficially positioned in the specifier position within CP. I argue that the wh-in-C analysis poses both developmental problems (in that it fails to account for child structures involving a preposed wh-phrase with an uninverted auxiliary) and potential theoretical problems (in that long movement of a wh-head may violate locality principles). I then consider two alternative accounts of wh-questions which posit that wh-movement involves movement of a wh-phrase from the very earliest stages of development. The first of these is an adjunction account, on which wh-phrases are analysed as clausal adjuncts in Child English (adjoined to the Verb Phrase (VP) in the earliest stages and to the Inflection Phrase (IP) in later stages). I note, however, that this provides no principled account of the absence of auxiliary inversion in child wh-questions, and poses continuity problems (especially within a framework such as that of Cinque (1990) in which it is assumed that wh-phrases never adjoin to VP or IP). Finally, I consider an alternative account on which initial wh-phrases are analysed as occupying the specifier position within CP at all stages of development. I note that the problem posed by this analysis is accounting for the absence of auxiliary inversion in early wh-questions, and offer an account which posits that children overgeneralize specifier-head agreement from IP to CP.

This paper explores the interface between syntax and pragmatics, focusing on the binding of pronouns and the pragmatics of the paradigms used to test this aspect of syntactic knowledge. Reinhart's (1986) version of Binding Theory (which accords a specific role to pragmatics in processes of pronoun resolution) and Sperber & Wilson's (1986) Theory of Relevance are used to examine the syntax and pragmatics of pronoun interpretation. A set of predictions based on Relevance Theory are evaluated against published results of tests of Binding Theory. The paper concludes that Relevance Theory provides a means of understanding constraints on testing syntactic knowledge and argues that pragmatic factors must be systematically controlled in any evaluation of syntactic knowledge.