In three studies, two-year-old children communicated to a parent which of two out-of-reach objects contained a sticker. Across trials, the objects were positioned in different configurations so that it was possible or impossible for a child's pointing gesture to unambiguously specify one object. In Study 1, the objects used were two boxes distinguished by a different picture of a vehicle on the front, and children (n = 16; mean age 2;8) were significantly more likely to name the box's picture on trials where pointing alone could not unambiguously specify the box than on trials where it could. In Studies 2 and 3, the stickers were hidden inside different animal figures. Older two-year-olds (n = 16, mean age 2;9), but not younger two-year-olds (n = 16, mean age 2;4), showed an ability to recognize the referential (in)efficacy of their pointing gestures and to adapt their communication accordingly.

The acquisition of the English past tense inflection is the paradigm example of rule learning in the child language literature and has become something of a test case for theories of language development. This is unfortunate, as the idiosyncratic properties of the English system of marking tense make it a rather unrepresentative example of morphological development. In this paper, I contrast this familiar inflection with a much more complex morphological subsystem, the Polish genitive. The genitive case has three different markers, each restricted to a different subset of nouns, in both the singular and the plural. Analysis of the spontanous speech of three children between the ages of 1;4 and 4;11 showed that they generalized, and overgeneralized, all three singular endings. However, error rates were extremely low and there is no evidence that they treated any one ending as the ‘default’. The genitive plural, on the other hand, showed a strikingly different pattern of acquisition, similar to that seen in English-speaking children learning the past tense. It is argued that in the latter two cases, the default-like character of one of the affixes is attributable to the properties of the relevant inflectional subsystems, not to the predispositions that children bring to the language-learning task.

This study considers the much-debated markedness and structural status of word-initial /s/-sequences in English by examining the development of KR (male, age 3;6) who has a phonological disorder. Three points in time are discussed: (1) when all initial consonant sequences are reduced to singletons; (2) when only initial /s/-sequences surface correctly; and (3) when all initial consonant sequences surface correctly. While these production patterns are common across developing systems, few accounts have addressed them in terms of structure or markedness. Toward that end, it is argued that KR's /s/-sequences surface as ADJUNCTS, rather than complex onsets. This is explained within optimality theory, whereby high-ranking markedness constraints prevent complex onsets but not adjuncts. The account offers an explanation for consonant sequence asymmetries within and across grammars, allowing for differing representations for /s/-sequences across speakers and for variation exhibited in children's productions. A typology of possible grammars is therefore offered, and clinical implications are considered.

The artificial language Esperanto is spoken not only as a second language, by its proponents, but also as a native language by children of some of those proponents. The present study is a preliminary description of some characteristics of the Native Esperanto (NE) of eight speakers, ranging in age from six to fourteen years. As such, it is the first of its kind – previous works on NE are either theoretical treatises or individual case studies. We find, at least for the eight subjects studied, both bilingualism and nativization effects, differentiating native from non-native Esperanto speech. Among these effects are loss or modification of the accusative case, phonological reduction, attrition of the tense/aspect system, and pronominal cliticization. The theoretical ramifications are discussed, particularly with regard to universals of language acquisition and the effects of expressive requirements of language.

Verbal/vocal interactions of three Japanese mother–child dyads were examined when the children were 1;0, 1;2 to 1;3, 1;6 to 1;7, and 1;8 to 1;9 to determine whether mothers provide information which may facilitate the elaboration of child lexical forms during the transition from the prelinguistic to the linguistic period. Mothers were likely to reproduce only the child's word-like utterances, both well- and ill-formed. This provided an opportunity for the child's ill-formed word-like utterance to be contrasted with an immediate maternal response. This finding, along with results showing within-child variability of lexical forms, suggested that maternal contrastive replies 1) signal errors to the child (cf. Saxton, 1997), and 2) may promote the child's selection and stabilization of production alternatives which are more accurate. Maternal reproductive responding presumably originated in their tendency to seek content-oriented communication, as was reflected in mother's growing inclination to continue verbal interactions following the child's non-word-like vocalizations.

Recently, much research has explored the role that nonverbal pointing behaviours play in children's early acquisition of language, for example during word learning. However, few researchers have considered the possibility that these behaviours may continue to play a role in language comprehension as children develop more sophisticated language skills. The present study investigates the role that eye gaze and pointing gestures play in three- to five-year-olds understanding of complex pragmatic communication. Experiment 1 demonstrates that children (N = 29) better understand videotapes of a mother making indirect requests to a child when the requests are accompanied by nonverbal pointing behaviours. Experiment 2 uses a different methodology in which children (N = 27) are actual participants rather than observers in order to generalize the findings to naturalistic, face-to-face interactions. The results from both experiments suggest that broader units of analysis beyond the verbal message may be needed in studying children's continuing understanding of pragmatic processes.

This paper investigates the relationship between a child's degree of bilingualism and features of parental input. It seeks to demonstrate that parental discourse strategies have a direct bearing on the levels of mixing present in the child's utterances in his weaker language, English. It is based on the longitudinal study of a Catalan/English bilingual child from 1;3 to 4;2 years old. The strategies adopted by both parents in response to their child's mixing are examined following Lanza's (1992, 1997) categorization of parental discourse strategies. Whereas the Catalan-speaking mother negotiates a bilingual context of interaction with her son, as of the child's third year, the English-speaking father endeavours to impose a monolingual context. Such a change of strategy clearly favours the child's increasing use of the minority language, which entails a sharp decline in rates of mixing. It appears that parents' pragmatic choices may have an impact on the development of productive family bilingualism.

In this study vocabulary development of a sample of 42 Italian children was evaluated through monthly administration of the Italian version of the CDI. Data collection started at 1;0–1;1 for 32 children and at 1;3–1;4 for the remaining subjects and continued until children's vocabulary reached 200 words. At fixed stages of vocabulary size (50, 100 and 200 words), individual differences in percentile scores and vocabulary composition were examined. Individual growth curves were analysed in order to verify the presence of a vocabulary spurt and the type of lexical items which contributed most to rapid acceleration in vocabulary growth.

Stylistic differences in vocabulary composition were examined regarding the ‘referential–expressive’ distinction, controlling vocabulary size. Data have shown that general trends in vocabulary development are quite similar to those obtained for other languages using CDI adaptations. Moreover, all children in this sample eventually exhibited a vocabulary spurt, even if some can be defined as ‘late spurters’. The type of lexical items which are learned during the spurt depend on both infant vocabulary size and referential score. About 28% of infants in this sample were defined ‘referential’ when their vocabulary size was about 50 words, but the stylistic differences disappeared at the 100- and 200-word stages.

Composition of vocabulary did not differ in relation to precocity in reaching different stages of vocabulary development. The only exception was that infants who reached the 50-word stage first also had a vocabulary with a lower proportion of function words.

Two common and seemingly independent error patterns, namely CONSONANT HARMONY and GLIDING, are examined for their typological characteristics based on cross-sectional and longitudinal evidence from young children's developing phonologies. Data are drawn from the published literature and from the developmental phonology archives at Indiana University. An asymmetry is observed such that the occurrence of harmony is found to imply the occurrence of gliding, but not vice versa. While this finding would be unexpected within contemporary derivational theories, it can be shown to follow within optimality theory from a fixed universal ranking relationship among certain constraints. Optimality theory is also argued to offer a viable developmental account with clinical implications that can serve as a further test of the theory.

Children who acquire Dutch as their first language show a strong preference for using infinitival verb forms during the early stages of grammatical development. This exemplifies the ‘root infinitive’ (RI) phenomenon, which has played a significant role in recent discussions on the development of syntax. Most accounts proposed thus far invoke an immaturity of the child's grammatical competence. We explore the possibility that the early predominance of infinitival forms is related to patterns in the language input. We analysed a corpus of utterances addressed by two Dutch-speaking mothers to their two- to three-year old sons. Root infinitive utterances amounted to 10%, and auxiliary-plus infinitive main verb constructions, which in terms of word order are maximally similar to RIs, constituted 30% of all verb-containing utterances. These figures render an account in terms of exposure to utterance structures unlikely. There is a moderate (but significant) correlation between frequency of occurrence of individual verb forms in the input and age of acquisition. However, infinitive verb forms are often acquired earlier than their input frequency would predict, and this may be related to an overall increased salience, due to their systematic appearance in sentence-final position and their relatively high conceptual transparency as compared to finite verbs.

This study investigated the interface of form and function in the acquisition of negation in Cantonese-speaking children. The data, from the Hong Kong Cantonese Child Language Corpus, were longitudinal spontaneous samples of eight children aged 1;5 to 3;8. The main issues of the study were the sequence of emergence of negative markers mou5, m4 and mei6 and the acquisition trend of 11 semantic categories of negation in children's expressive language. The acquisition trend of the semantic categories matched Bloom's (1970, 1991a) finding that Non-existence preceded Rejection and Denial.

Four experiments examine the child's ability to draw on functional information to predict the similarity of function across exemplars and to extend new words from an initial exemplar to one of two others. Experiments 1 and 2 tested 16 three- and four-year-olds each (mean ages: 4;5 and 4;4, in Experiments 1 and 2, respectively) and reveal that three- and four-year-olds are able to predict similarity of function and to extend new words on the basis of function if the function is based on shape, but not if the function is based on material makeup. Experiment 3 tested 53 older children, at three age groups (mean ages: 7;2, 8;3, 9;10) and suggests that seven-year-olds have more difficulty in judging similarity of function on the basis of material makeup than eight- and nine-year-olds, and that nine-year-olds are more likely than seven- and eight-year-olds to use functional information to extend new words. Experiment 4 tested 108 children in two age groups (with mean ages of 7;9 and 9;8) and reveals that when function is pitted against syntax as criteria for categorization under a new name, seven-year-olds are more attentive to syntax than nine-year-olds, while nine-year-olds are more attentive to function than seven-year-olds. The cognitive difficulties associated with judgements concerning material function are discussed in relation to additional factors that could lead children under age nine to perform in a non-adult-like fashion in the extension of new names.

This study investigates the role of performance limitations in children's early acquisition of verb-argument structure. Valian (1991) claims that intransitive frames are easier for children to produce early in development than transitive frames because they do not require a direct object argument. Children who understand this distinction are expected to produce a lower proportion of transitive verb utterances early in development in comparison with later stages of development and to omit direct objects much more frequently with mixed verbs (where direct objects are optional) than with transitive verbs. To test these claims, data from nine children aged between 1;10.7 and 2;0.25 matched with Valian's subjects on MLU were examined. When analysed in terms of abstract syntactic structures Valian's findings are supported. However, a detailed lexical analysis of the data suggests that the children were not selecting argument structure on the basis of syntactic complexity. Instead, a clear predictor of the frames used by the children with specific verbs was the frames used by the children's mothers with those same verbs, regardless of whether they were transitive or intransitive. This suggests that the most important determinant of the children's use of verb frame was the specific patterns of verb use in the input rather than abstract grammatical knowledge constrained by performance limitations. The implications of these findings for performance-based explanations for children's early errors and early patterns of language use are discussed.

This study investigated the ASPECT FIRST HYPOTHESIS which claims that children initially use verbal morphology to mark aspect and not tense. Experiment 1 tested 46 two- and three-year-old children's comprehension of tense as it is marked in the auxiliary system using a sentence-to-scene matching task. Children were presented with multiple performances of the same event and asked where a character is V'ing, was V'ing and is gonna V. Results showed that even the two-year-old children could successfully understand tense in this experiment. Experiment 2 changed the information available in the scenes by varying whether or not the past-time event reached its completion point. Thirty-six two-, three- and four-year-old children participated. The results showed that the two-year-olds could only successfully understand past and present auxiliaries when past-time information in the scenes was co-extensive with completion information in the scenes. This result suggests that these children may be making a grammatical aspect (perfective/imperfective) judgment and not a tense (past/present) judgment, or at least, that grammatical aspect influences tense interpretation for these children.

This study investigates acquisition of the rhyme using cross-sectional and longitudinal data from 14 English-speaking children (aged 1;3–2;0). It focuses on 4 questions pertaining to rhyme development, which are motivated from current theories of prosodic acquisition: 1. Do children make vowel length errors in early acquisition?; 2. Do children acquire coda consonants before they learn the vowel length contrast?; 3. What consonants are first acquired as codas?; and 4. Is there a size constraint such that children's productions are minimally and maximally bimoraic? The results indicate that the percentage of vowel length errors across all children was low irrespective of the percentage of codas produced. In particular, two children produced very few coda consonants and made few vowel length errors, suggesting that mastery of vowel length was not secondary to coda acquisition. With respect to coda segments, children produced voiceless obstruents as codas before sonorants supporting generally the claim that obstruents emerge before sonorants in coda position. Children produced coda consonants more frequently after short than long vowels consistent with a bimoraic size constraint in syllable development. The paper concludes by comparing the English findings with cross-linguistic work on vowel length acquisition.

Animals are distinctive in that they are the causal agents of their own actions (e.g. a dog moves itself), whereas artifacts generally are not (e.g. a marble doesn't move itself). We examined whether children make use of this conceptual link between animacy and agency when interpreting the verb ‘move’ in English. Specifically, we hypothesized that the semantic interpretation of ‘move’ would differ, depending on whether the subject noun refers to an animal or to an inanimate object. We hypothesized that, for inanimates, children would allow ‘move’ to have a patient subject (e.g. ‘the marble moved’ could mean ‘the marble was moved by someone else’) but not so for animates (e.g. ‘the dog moved’ could not mean ‘the dog was moved by someone else’). In two studies, 65 three-year-olds, 57 five-year-olds, and 74 adults viewed video clips of animals or inanimate objects being transported by a person. For each clip, the child was asked whether the animal or object was moving. A ‘yes’ response would indicate acceptance of a patient subject (e.g. ‘the dog/marble moved’ means ‘the dog/marble was moved by someone else’). Both five-year-old children and adults more often reported that the toys were moving, than that the animals were moving. However, three-year-olds showed no animacy effects. Thus, between the ages of three and five, children begin to link animacy and agency in language. These findings suggest that children's language use is guided by similar conceptual constraints as those of adults, and/or that children are sensitive to distributional information linking form and meaning in the input language.

Rules for interpreting empty category (EC) subjects of complement clauses vary crosslinguistically across structural and lexical dimensions. In adult Greek, a distinction is made between the verbs meaning WANT and TRY, the former but not the latter permitting the EC subject of its subjunctive complement to refer outside the sentence. The EC is pro for WANT and PRO for TRY. In adult Spanish, both the verbs meaning WANT and TRY require the EC subject (pro) to refer outside when the complement is in the subjunctive, and require the EC subject (PRO) to refer to the main clause subject when the complement is in the infinitive. Twenty-three Greek-speaking four- to five-year-olds and 10 adults, 29 Spanish-speaking four- to five-year-olds, 18 six- to seven-year-olds and eight adults took part in act-out experiments. The results indicate an awareness of language-particular distinctions governing the interpretation of EC complement subjects. However, child speakers of both languages experience difficulty in giving sentence external reference, leading to error in the case of subjunctive sentences for Spanish-speaking children. We argue that the data overall is most compatible with children having access to the empty category PRO by age four, and that failure to give external reference of an EC when required can plausibly be treated as performance error. A picture verification task produced less clear results, but points to the need for data from younger children to establish whether there is an early stage in which lexical semantics dominates children's interpretation of ECs.

The current study analysed article use in Spanish-speaking children with specific language impairment who are learning English as a second language. The SURFACE HYPOTHESIS account of specific language impairment was evaluated in relation to the use of articles in these children. Language samples were obtained from 15 Spanish-speaking children with language impairment and 15 with normal language, ages 5;0 to 7;1, matched by age, gender, and school. The percentage of article errors was tested between groups with a nonparametric analysis and an analysis of covariance with mean length of terminable unit as the covariate. Results revealed significant differences between groups on percent of article errors with and without MLTU as the covariate. Nonparametric statistics on percent of article error types indicated that most errors consisted of omissions and gender agreement substitutions. As predicted by the Surface Hypothesis, article errors were likely to occur in unstressed definite articles, suggesting that perceptual and prosodic processes have some impact on children's production of articles.

Three studies, designed to examine use of word order and animacy for interpretation of sentences by 21 typically-developing two-year-old, 23 typically-developing two-and-one-half-year-old, 16 typically-developing three-year-old, 17 language-delayed two-and-one-half-year-old and 19 language-delayed three-year-old children were carried out. Results indicated that typically-developing two-year olds used neither cue consistently to interpret sentences. Typically-developing two-and-one-half-year olds, on the other hand used a coalition of word order and animacy cues and language-delayed two-and-one-half-year olds used neither cue. At three years of age both groups of children used word order exclusively to interpret sentences.

The development of metalinguistic awareness, and specifically syntactic awareness, (here measured by age-related changes in the ability to judge and revise unacceptable sentences), reflects developmental changes in focus from semantic to syntactic properties of sentences. Previous research reported that children find judgements of word-order changes easier than morphological violations (Hakes, 1980). We hypothesized that this difference in ease of judgement is linked to the language under investigation. That is, there may be a relationship between the functional load of grammatical morphemes and ability to detect syntactic violations. This study investigated the development of syntactic awareness in Cantonese-speaking children. Fifty-six subjects from four age groups (three, five, seven and 20 years old) were asked to judge the grammaticality of 40 sentences (18 with word-order changes and 22 with morphological violations) and correct the grammatically deviant sentences. There was a significant age effect on subjects’ performance in both judgement and revision tasks. Children scored significantly higher in judging sentences with word order changes than those with morphological violations. They also scored higher on word order revisions than morphological revisions, an unexpected finding. The success of correcting morphological violations varied by morphological marker, apparently according to each marker's degree of obligatory use in the language. It would seem then that syntactic awareness is very much affected by language-specific characteristics.