Type/Token Ratios have been extensively used in child language research as an index of lexical diversity. This paper shows that the measure has frequently failed to discriminate between children at widely different stages of language development, and that the ratio may in fact fall as children get older. It is suggested here that such effects are caused by a negative, though non-linear, relationship between sample size (i.e. number of tokens) and Type/Token Ratio. Effects of open and closed class items are considered and an alternative Verbal Diversity measure is examined. Standardization of the number of tokens before computing Type/Token Ratios is recommended.

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.

The hypothesis that prelinguistic vocalizations contain extensive and systematic sound-meaning correspondences was examined through an exhaustive analysis of the babbling of five infants in their second year. These infants were videotaped over a period of three to six months at home and at a day-care centre. Their babbled utterances were transcribed phonetically and categorized according to consonant-type and vowel-type. Contexts for each utterance were also categorized, primarily according to the infant's simultaneous action. A quantitative analysis of co-occurrences between phonetic and contextual categories determined that across infants between 14 and 40% of utterances recurred in particular contexts with a greater than expected frequency. These findings support Halliday's (1975a) notion that babbling is not entirely random but contains consistent sound-meaning relations that are not adult-modelled. They also extend the notions of continuity between prelinguistic and linguistic stages of development to the semantic domain.

The communicative functions of pitch direction and pitch range during the second year were investigated. The research focusses on initial plus repeated requests, either for objects or for co-operation, which were contrasted against giving, showing and labelling. Infants aged 1; 2 to 1;10 were observed in interaction with their mothers in a semistructured situation. Vocalizations were coded separately for communicative function and for prosodic features. Results show that pitch range is consistently higher (1) for repeated requests than for initial requests for objects and (2) for initial requests for objects and for co-operation than for labelling. Giving and showing have an intermediate rank between requests and labelling. Trends in prosodic contours were observed in both requests and labelling: rising tones were more frequently associated with requests whereas falling tones appeared more often in conjunction with labelling.

The language of mothers and fathers to their toddler sons and daughters at play with three different types of toy was analysed for both sentence types and structural elements. Two of the play contexts, dolls and vehicles, were highly sex-role stereotyped, and the third, shape sorters, was neutral. Few differences in speech were found as a function of either parent or child gender. Each of the three play contexts, however, elicited its own language pattern. With dolls, parental speech was characterized by a relatively large amount of language and a frequent use of questions and nouns, especially by contrast with vehicle play, which involved little language. Play with shape sorters elicited a high proportion of directives and attentionals and a relatively low variety in language. These results suggest that children who play frequently with dolls may receive more opportunities to learn and practise language than do children who select other toys for play. In this way early toy preferences may contribute to differential socialization by parents.

The phonological acquisition of a young girl whose parents spoke two dialects of Cantonese was examined. The father's dialect had a phonological distinction between initial /l/ and /n/ which was merged into /l/ in the mother's dialect. The child was followed bi-weekly for approximately one year. The results indicate that she acquired neither the mother's nor the father's dialect. Instead, she acquired [l] and [n] as freely varying allophones of a single phoneme. In the first months, [n] was the most frequent realization of the phoneme, with [l] becoming the most frequent one in later sessions. The results are interpreted as supporting the claim that children use all available input in acquiring language rather than limiting themselves to a primary language model.

This paper presents the results of two experiments which appear to show that children's linguistic generalizational biases change from a semantically based system to a syntactic-structural system. The experiments use the constituent repetition paradigm of Read & Schreiber (1982). Subjects were trained to repeat the subject noun phrase in orally presented sentences. Preschoolers, but not second-graders, displayed a tendency to repeat the agentive noun phrase (contained in the by-phrase) in semantically irreversible passive sentences. It is argued that the results provide more evidence for a semantic-relational bias in children's early grammars, and that the results also provide support for the notion that children's generalizational biases shift from a semantic relational basis to a syntactic-structural basis some time between the preschool and early grammar school years.

Developmental differences in object word learning and use were investigated. Two groups of infant speakers: Beginner (vocabularies under 50 words) and Advanced (vocabularies over 50 words), participated in a concept formation and word learning and generalization experiment. Results indicated that both speaker groups formed concepts of and learned words for the to-be-learned objects, and generalized these words. However, Advanced speakers learned more concepts and words, and engaged in broader generalization than Beginner speakers. The following variables did not account for these developmental differences: child age, object permanence development, maternal speech, child action on objects. These findings can be explained by developmental differences in both the number and kind of object concepts formed in the second year. Words were primarily acquired for object concepts by both speaker groups. However, Beginner speakers formed fewer concepts, thus having a less extensive conceptual base supporting word learning. This may account for their lower levels of vocabulary acquisition. Additionally, Beginner speakers appear to form prototype/exemplar-based object concepts, leading to limited word extension, while Advanced speakers form featurally based object concepts, leading to broader extension.

Will adults whose native language is English and children whose native language is Spanish follow the same strategies in acquiring the category of noun gender and its functions in Spanish? This investigation shows that there are significant differences in first- and second-language acquisition. Performance on five tasks eliciting responses containing gender agreement was measured for two groups. Results suggest that there is a developmental progression in acquisition of noun gender for both groups. Nevertheless, on tasks containing grammatical and/or semantic conflict, even the linguistically least-experienced adults reflected correct, adult-like strategies for Spanish gender agreement, whereas only the oldest children performed in this manner.

The productive narrative competence of three young children as revealed in their spontaneously occurring conversations recorded over an 18-month period during their kindergarten and grade one years was investigated. Almost 90 hours of the children's conversations, produced as they were being driven to and from school, were audiotaped and analysed in order to determine whether children between the ages of five and seven include narrative accounts in their conversations with each other and, if so, the nature of the narrative language produced. The subjects were found routinely and regularly to produce a striking variety of narrative forms; 14 different narrative types were distinguished and defined, six of which have not previously been reported in the literature on children's narratives. Seventy per cent of the recorded narratives took anecdotal form; original fantasy narratives occurred only rarely. A significant proportion of the narratives were collaboratively created.

The connective and has frequently been described as a useful allpurpose connective that is used as a vehicle for introducing new inter-sentential semantic relationships. As new and more specific connectives are acquired, they are matched to these meanings. An assumption is that as children get older, and should be used less to express the various meanings for which more specific connectives exist; rather, it should be increasingly reserved for simple co-ordination. This hypothesis was tested by examining narratives produced by children between 4 and 9 years old; contrary to expectation, and was used no differently by 9-year-olds than by 4-year-olds, and simple co-ordination constituted no more than 20% of the relationships. The role of and may be to indicate cohesion between sentences, without regard to semantic relationship.