This cross-linguistic study investigates children's early lexical development in English and Korean, and compares caregivers' linguistic input in the two languages. In Study 1, the lexical development of nine Korean children was followed from 1;2 to 1;10 by monthly visits and maternal reports. These Korean data were compared to previously collected English longitudinal data. We find that: (1) Korean children as young as 1;3 use verbs productively with appropriate inflections. (2) Seven of the nine children show a verb spurt at around 1;7; for six of these children the verb spurt occurs before the noun spurt. No such early verb spurt is found in the English data. Unlike in English, both verbs and nouns in Korean are dominant categories from the single-word stage. (3) Korean children express language-specific distinctions of locative actions with verbs. Study 2, a crosslinguistic study of caregivers' input in English and Korean, shows that Korean mothers provide more action verbs but fewer object nouns than American mothers. Also, Korean mothers engage in activity-oriented discourse significantly more than American mothers. Our study suggests that verbs are accessible to children from the beginning, and that they may be acquired early in children who are encouraged to do so by their language-specific grammar and input.

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.

Research using online comprehension measures with monolingual children shows that speed and accuracy of spoken word recognition are correlated with lexical development. Here we examined speech processing efficiency in relation to vocabulary development in bilingual children learning both Spanish and English (n=26 ; 2 ; 6). Between-language associations were weak: vocabulary size in Spanish was uncorrelated with vocabulary in English, and children's facility in online comprehension in Spanish was unrelated to their facility in English. Instead, efficiency of online processing in one language was significantly related to vocabulary size in that language, after controlling for processing speed and vocabulary size in the other language. These links between efficiency of lexical access and vocabulary knowledge in bilinguals parallel those previously reported for Spanish and English monolinguals, suggesting that children's ability to abstract information from the input in building a working lexicon relates fundamentally to mechanisms underlying the construction of language.

This study investigated the relationships between children's linguistic environments and their language acquisition. Speech samples taken from seven firstborn children and their mothers when the children were 1; 6 and 2; 3 were analysed within a number of semantic and syntactic categories to determine correlations between mothers' speech and subsequent language development. Several characteristics of mothers' speech (e.g. utterance length, use of pronouns) significantly predicted later child speech. The significant correlations suggested that mothers' choice of simple constructions facilitated language growth. Further, they showed that the motherese code differed from adult-adult speech in ways which aided language development. Differences between our study and previous investigations of environmental effects on language development probably resulted from the failure of earlier investigations to take into account children's level of language competence at the time when environmental effects were assessed.

This study investigated the changing functions of evaluative devices in children's narratives. The evaluative devices included (a) references to ‘frames of mind’, particularly to emotions, (b) character speech, (c) ‘hedges’, (d) negative qualifiers, and (e) causal connectors. Narratives were elicited from a 24-picture story book. The subjects were three groups of native English-speaking Americans (12 per group): five- and nine-year-old children and college undergraduate students. A quantitative comparison revealed that (i) adults used evaluative devices three times as often as five-year-olds, and two-and-a-half times as often as the nine-year-old children; (ii) adults used significantly more references to ‘frames of mind’ and ‘hedges’ than the children; and (iii) whereas five-year-olds used each evaluative type equally often, nine-year-olds and adults used references to ‘frames of mind’ significantly more than the other four evaluation types. A second analysis, focusing specifically on the discourse functions of references to ‘frames of mind’ revealed that, early on, this particular device is used to express a local evaluative perspective on particular events, while with increasing age it is used to signal the hierarchial organization of the story events. These findings are discussed with regard to two non-linguistic developmental achievements, the formation of event schemas and the formation of a theory of mind.

The acquisition of connective forms and the meaning relations between connected clauses in the development of complex sentences is described for four children from two to three years of age. The major results of the study include the developmental interactions between syntactic connectives and meaning relations, and between these interactions and the discourse environments in which they occurred. The first syntactic connective the children learned, and, was the most general: semantically, and was used to encode conjunction with all of the different conjunction meaning relations in the order Additive < Temporal < Causal < Adversative. Other connectives were semantically more specific, and were learned subsequently with different syntactic structures in the order Conjunction < Complementation < Relativization. These results are discussed in terms of FORM, relative linguistic complexity; CONTENT, the intersection of form with conceptual and semantic factors affecting acquisition; and USE, discourse cohesion.

In this paper, I review properties and consequences of the PRINCIPLE OF CONTRAST. This principle, which I have argued from the beginning has a pragmatic basis, captures facts about the inferences speakers and addressees make for both conventional and novel words. Along with a PRINCIPLE OF CONVENTIONALITY, it accounts for the pre-emption of novel words by well-established ones. And it holds just as much for morphology as it does for words and larger expressions. In short, Contrast has the major properties Gathercole (1989) proposed as characteristic of her alternative to Contrast.

An investigation of children's ability to convey and respond to requests for action was based on the spontaneous speech of 36 dyads of nursery school children (3; 6–5; 7). Direct request forms (e.g. Give me the hammer) were frequent and the majority were acknowledged verbally. Examination of the contexts of direct requests indicated that speaker and addressee shared an understanding of the interpersonal meaning factors relevant to requesting. These meaning factors were invoked in justifying, refusing and in repeating or paraphrasing a request, and they also provided a basis for the communication of indirect requests. Examples of inferred requests are discussed, and a relationship between the structure of the speech act and conversational sequences is proposed.

This paper provides an overview of the features of caregiver input that facilitate language learning across early childhood. We discuss three dimensions of input quality: interactive, linguistic, and conceptual. All three types of input features have been shown to predict children's language learning, though perhaps through somewhat different mechanisms. We argue that input best designed to promote language learning is interactionally supportive, linguistically adapted, and conceptually challenging for the child's age/level. Furthermore, input features interact across dimensions to promote learning. Some but not all qualities of input vary based on parent socioeconomic status, language, or culture, and contexts such as book-reading or pretend play generate uniquely facilitative input features. The review confirms that we know a great deal about the role of input quality in promoting children's development, but that there is much more to learn. Future research should examine input features across the boundaries of the dimensions distinguished here.

Cross-linguistic similarities and differences in early lexical and grammatical development are reported for 1001 English-speaking children and 386 Italian-speaking children between 1;6 and 2;6. Parents completed the English or Italian versions of the MacArthur Communicative Development Inventory: Words and Sentences, a parent report instrument that provides information about vocabulary size, vocabulary composition and grammatical complexity across this age range. The onset and subsequent growth of nouns, predicates, function words and social terms proved to be quite similar in both languages. No support was found for the prediction that verbs would emerge earlier in Italian, although Italians did produce a higher proportion of social terms, and there were small but intriguing differences in the shape of the growth curve for grammatical function words. A strikingly similar nonlinear relationship between grammatical complexity and vocabulary size was observed in both languages, and examination of the order in which function words are acquired also yielded more similarities than differences. However, a comparison of the longest sentences reported for a subset of children demonstrates large cross-linguistic differences in the amount of morphology that has been acquired in children matched for vocabulary size. Discussion revolves around the interplay between language-specific variations in the input to young children, and universal cognitive and social constraints on language development.

We designed a parent-directed home-visiting intervention targeting socioeconomic status (SES) disparities in children's early language environments. A randomized controlled trial was used to evaluate whether the intervention improved parents' knowledge of child language development and increased the amount and diversity of parent talk. Twenty-three mother–child dyads (12 experimental, 11 control, aged 1;5–3;0) participated in eight weekly hour-long home-visits. In the experimental group, but not the control group, parent knowledge of language development increased significantly one week and four months after the intervention. In lab-based observations, parent word types and tokens and child word types increased significantly one week, but not four months, post-intervention. In home-based observations, adult word tokens, conversational turn counts, and child vocalization counts increased significantly during the intervention, but not post-intervention. The results demonstrate the malleability of child-directed language behaviors and knowledge of child language development among low-SES parents.

The phonological acquisition of 129 monolingual Putonghua-speaking children, aged 1; 6 to 4; 6, is described. Putonghua (Modern Standard Chinese) syllables have four possible elements: tone, syllable-initial consonant, vowel, and syllable-final consonant. The children's errors suggested that Putonghua-speaking children mastered these elements in the following order: tones were acquired first; then syllable-final consonants and vowels; and syllable-initial consonants were acquired last. Phonetic acquisition of the 21 syllable-initial consonants was complete by 3; 6 for 75% of children. By 4; 6 the children were using the syllable-initial consonants correctly on two thirds of occasions (with the exception of four affricates). Simple vowels emerged early in development. However, triphthongs and diphthongs were prone to systematic errors. Tone errors were rare, perhaps because of their role in distinguishing lexical meaning. In contrast, acquisition of ‘weak stress’ and ‘rhotacized feature’ was incomplete in the oldest children assessed. Phonological processes used by the children were identified. Two of these processes, syllable-initial consonant deletion and backing, would be considered atypical error patterns in English. Existing theories of phonological acquisition (e.g. concepts of markedness, functional load, feature hierarchies) cannot account for some of the patterns revealed. A satisfactory explanation of the findings requires more attention to the specific characteristics of the linguistic system the children are learning. It is proposed that the saliency of the components in the language system determines the order of acquisition.

Recent studies indicate that young English-speaking children do not have a general understanding of the significance of SVO order in reversible sentences; that is, they seem to rely on verb-specific formulas (e.g. NPpusher – form of the verb PUSH – NPpushee) to interpret such sentences (Akhtar & Tomasello, 1997). This finding raises the possibility that young children may be open to learning non-SVO structures with novel transitive verbs. To test this hypothesis, 12 children in each of three age groups (two-year-olds, three-year-olds, and four-year-olds) were taught novel verbs, one in each of three sentence positions: medial (SVO), final (SOV), and initial (VSO). The younger age groups were equally likely to use the novel (non-English) orders spontaneously as to correct them to SVO order, whereas the oldest children consistently corrected these structures to SVO order. These results suggest that English-speaking children's acquisition of a truly general understanding of SVO order may be a gradual process involving generalization (learning) from examples. The findings are discussed in terms of recent data-driven learning accounts of grammar acquisition.

The ability of children between the ages of 2; 0 and 4; 8 to produce locative pre- or postpositions was investigated in English, Italian, Serbo-Croatian, and Turkish. Across languages, there was a general order of development: (1) ‘in’, ‘on’, ‘under’, and ‘beside’, (2) ‘between’, ‘back’ and ‘front’ with featured objects, (3) ‘back’ and ‘front’ with non-featured objects. This order of development is discussed in terms of nonlinguistic growth in conceptual ability. Language-specific differences in the general pattern of development are discussed in terms of a number of linguistic factors which may facilitate or retard the child's discovery of the linguistic means for encoding concepts.

Similarity neighbourhoods for words in young children's lexicons were investigated using three computerized databases. These databases were representative of three groups of native English speakers: 5-year-olds, 7-year-olds, and adults. Computations relating to the similarity neighbourhoods of words in the children's and adult's lexicon revealed that words in the 5- and 7-year-olds' lexicons have many fewer similar neighbours than the same words analyzed in the adult lexicon. Thus, young children may employ more global recognition strategies because words are more discriminable in memory. The neighbourhood analyses provide a number of insights into the processes of auditory word recognition in children and the possible structural organization of words in the young child's mental lexicon.

This paper describes the early lexical development of a group of 328 normal Spanish-speaking children aged 0;8 to 2;7. First the development and structure of a new parent report instrument, Inventario del Desarollo de Habilidades Communcativas is described. Then five studies carried out with the instrument are presented. In the first study vocabulary development of Spanish-speaking infants and toddlers is compared to that of English-speaking infants and toddlers. The English data were gathered using a comparable parental report, the MacArthur Communicative Development Inventories. In the second study the general characteristics of Spanish language acquisition, and the effects of various demographic factors on that process, are examined. Study 3 examines the differential effects of three methods of collecting the data (mail-in, personal interview, and clinic waiting room administration). Studies 4 and 5 document the reliability and validity of the instrument. Results show that the trajectories of development are very similar for Spanish-and English-speaking children in this age range, that children from varying social groups develop similarly, and that mail-in and personal interview administration techniques produce comparable results. Inventories administered in a medical clinic waiting room, on the otherhand, produced lower estimates of toddler vocabulary than the other two models.

This study tests the widely-cited claim from Volterra & Taeschner (1978), which is reinforced by Clark's Principle Of Contrast (1987), that young simultaneous bilingual children reject cross-language synonyms in their earliest lexicons. The rejection of translation equivalents is taken by Volterra & Taeschner as support for the idea that the bilingual child possesses a single-language system which includes elements from both languages. We examine first the accuracy of the empirical claim and then its adequacy as support for the argument that bilingual children do not have independent lexical systems in each language. The vocabularies of 27 developing bilinguals were recorded at varying intervals between ages 0;8 and 2;6, using the MacArthur GDI, a standardized parent report form in English and Spanish. The two single-language vocabularies of each bilingual child were compared to determine how many pairs of translation equivalents (TEs) were reported for each child at different stages of development. TEs were observed for all children but one, with an average of 30% of all words coded in the two languages, both at early stages (in vocabularies of 2–12 words) and later (up to 500 words). Thus, Volterra & Taeschner's empirical claim was not upheld. Further, the number of TEs in the bilinguals' two lexicons was shown to be similar to the number of lexical items which co-occurred in the monolingual lexicons of two different children, as observed in 34 random pairings for between-child comparisons. It remains to be shown, therefore, that the bilinguals' lexicons are not composed of two independent systems at a very early age. Furthermore, the results appear to rule out the operation of a strong principle of contrast across languages in early bilingualism.

This paper presents a detailed analysis of early lexical and phonological development in three children. The study covers the period from late babbling through the acquisition of 50 conventional words and focuses on: (1) the relationship between prelinguistic and linguistic vocalizations; (2) phonological development after the onset of speech; (3) patterns of lexical selection; (4) rate of lexical acquisition; and (5) use of invented words. The findings reveal that while the prelinguistic utterances of the children were similar, there was extensive inter-subject variation after the onset of meaningful speech, particularly in the segmental and syllabic forms of word productions, patterns of lexical selection, rate of lexical acquisition, and use of invented words.

Two groups of 20 infants aged 0; 3 experienced either conversational turn taking or random responsiveness of an adult. All infant vocalizations were counted and then each was categorized as a speech-like (syllabic) sound or a nonspeech-like (vocalic) sound. The results of this experiment indicated that turn taking caused changes in the quality of infant vocal sounds. When the adult maintained a give-and-take pattern, the infant produced a higher ratio of syllabic/vocalic sounds. The effect of turn taking on infant vocalizations was discussed in terms of its possible adaptive value for adult responsiveness.

A new corpus of spontaneous conversations between adults and children is examined for evidence that adults simplify their vocabulary choices when speaking with young children. If these simplifications are found to be age-dependent, then they would broaden the pattern of simplifications characteristic of ‘motherese’ to include lexical choice as well. For the age-range newborns to 12 years, the results are both consistent with and contrary to the attested set of grammatical simplifications. In this corpus, MLU and TTR are strongly age-dependent, but adults do not choose their words from the 10,000 most common word-types in English in an age-dependent manner. Rather, the additional types for school-aged children come from the same part of the vocabulary and share the same-shaped distributions as in adult speech with preschool children and infants. This absence of an age-dependent accommodation in word choice has implications for models of child lexical acquisition which assume adult language accommodation.