This study evaluates how language exposure and mothers’ language dominance relate to infants’ early bilingual vocabulary development in a low-socioeconomic status (SES) sample from an understudied population: Mexican Indigenous bilinguals. Thirty-two mother–child dyads participated. All mothers were bilingual speakers of Spanish and one of Mexican Indigenous languages, including Zapotec, Mixtec, and Otomi. Infants’ (between 16 and 37 months) vocabulary size was estimated in both languages using the Mexican Spanish version of the MacArthur-Bates CDI II. Infants’ language exposure, mothers’ bilingual profile, and their SES were estimated on numerical scales. The results of Spearman correlations showed infants’ vocabulary size in Spanish grows with age, while their vocabulary in the Indigenous language depends on relative language exposure. Mothers’ language dominance correlated with Indigenous language exposure and infants’ vocabulary size in the Indigenous language. These findings are discussed in the context of early bilingual vocabulary acquisition in speakers of minority languages.

In order to examine the extent to which adult judgments of first words depend on visual and auditory cues, spontaneous utterances were collected for boys and girls of 1; 5, 1; 6 and 1; 10 as well as adults naming the same toys. Vocalizations clearly appropriate to the original visual context were dubbed onto new contexts varying in the number of phonetic features (0-2) by which the first phoneme of the utterance differed from the initial phoneme labelling the visual context. College students' perceptual accuracy declined with degree of mismatch, although the identical speech occurred in each context. The older the speaker, the less perception was affected by visual context. Whereas the meaning of child speech was judged by visual cues, adult meanings were judged mostly by auditory input. Biases in perceiving early speech may prompt reconsideration of current methodology and theory in early language acquisition.

It is not unusual for developmental psychologists to become frustrated with the theory of universal grammar (UG), whose proponents have tended to dismiss most research on children's language production and comprehension as irrelevant to explaining how human languages are acquired. This is because children's actual linguistic behaviour is presumed to reflect factors besides their grammatical competence, rendering most methods of sampling linguistic behaviour unsuitable for evaluating UG theory. This means, in practice, that UG proponents do not view performance errors as evidence against their hypothesis that grammatical knowledge is largely innate. When children perform at ceiling on a given task, this is usually taken as proof of their adultlike grammatical competence, while poor performance is dismissed as due to research design flaws or limitations in information processing capacities (e.g. working memory). Crain & Thornton (1998) attempt to eliminate what they consider to be post hoc processing accounts of children's linguistic behaviour by arguing, counter to Chomsky (1965) and many others, that children and adults share identical language processing mechanisms, and that linguistic performance directly reflects grammatical competence. Therefore, if UG principles are available from an early age, child and adult performance should be the same when tasks are properly constructed to avoid extra-linguistic demand characteristics (excepting adult–child differences predicted by parameter-setting or maturational models). It should not be surprising then that some psycholinguists, such as Drozd (target article), would find C&T to be misguided with respect to these issues, because children's linguistic behaviour surely differs from adults' in seemingly unpredictable ways.

We examined the effects of object attributes on children's descriptive patterns in a referential communication task. Thirty preschoolers described object pairs that were selected by the experimenter. The targets were defined by shared size or colour, and differed on the non-target dimension in half of the trials. The children also completed a non-verbal reasoning task with analogous stimuli. They selected objects after observing the experimenter make a choice and inferring the basis for selection. In the communication task, the children produced fewer size than colour descriptions, particularly when the size targets differed in colour. They also over-specified colour features more often than size. They did not show a similar challenge identifying size relationships in the non-verbal task. The results support the conclusion that target attributes have a systematic influence on children's referential performance. Potential mechanisms for these effects, and directions for future research are discussed.

We enjoyed reading Matthew Rispoli's review of Rethinking innateness (henceforth RI-Elman et al. 1996). First, we respond to what we see as the major issues that he raises. Finally, we respond to the commentaries contributed by other authors in this issue.

Rispoli has two major concerns. First, he fears that RI will do the field a great disservice, increasing polarization and sowing discontent. To some extent this is an ‘eye of the beholder’ criticism that is difficult to counter: if Rispoli feels more polarized upon reading this book, who are we to argue?

Non-obligatory control constructions (NOC) are sentences which contain a non-finite clause with a null subject whose reference is determined pragmatically. Little is known about how children assign reference to these subjects, yet this is important as our current understanding of reference-resolution development is limited to less complex sentences with overt elements, such as pronouns. This study explores how seventy-six children (aged six to eleven) consult pragmatic leads when assigning reference in two examples of NOC. Children undertook three picture-selection tasks, containing no lead, a weak lead, and a strong lead, and their reference choices in the critical sentences were monitored. The novel results pinpoint children's baseline interpretations of the ambiguous sentences and expose an age trend in the degree to which they consult strong pragmatic leads when resolving reference. These trends illustrate how reference assignment in more complex discourse-governed contexts progresses, thereby contributing an important dimension to the pragmatics acquisition literature.

Although previous research has indicated that five-year-olds can use acoustic cues to disambiguate compounds (N1 + N2) from lists (N1, N2) (e.g., ‘ice-cream’ vs. ‘ice, cream’) (Yoshida & Katz, 2004, 2006), their productions are not yet fully adult-like (Wells, Peppé & Goulandris, 2004). The goal of this study was to examine this issue in Australian English-speaking children, with a focus on their use of F0, word duration, and pauses. Twenty-four five-year-olds and 20 adults participated in an elicited production experiment. Like adults, children produced distinct F0 patterns for the two structures. They also used longer word durations and more pauses in lists compared to compounds, indicating the presence of a boundary in lists. However, unlike adults, they also inappropriately inserted more pauses within the compound, suggesting the presence of a boundary in compounds as well. The implications for understanding children's developing knowledge of how to map acoustic cues to prosodic structures are discussed.

The commentators on this review raised many interesting and important points, and I am grateful to each of them for their time and their thoughtfulness. Each commentary deserves a thorough discussion of its own, but unfortunately, due to extreme limitations of space, I will have to focus here on what I see as the major points raised by one or more of them.

The authors of this rich and interesting paper have done a fine service to the field of child language by bringing to the forefront the largely neglected topic of later language development. Major discourse-oriented studies including children beyond preschool age have been confined to oral production of narrative texts (Peterson & McCabe, 1983; Berman & Slobin, 1994; Hickmann, in press), and they all leave off at around age ten. The pathbreaking work of Labov (1972) did in fact consider the language of pre-adolescents and teenagers in explicitly linguistic terms, but this also concerned oral narratives without focusing on development. One important contribution of the present study, then, is to show that the progression from early school-age via middle childhood and on to adolescence and adulthood involves far more than merely increased vocabulary.

The study evaluated whether durational and allophonic cues to word boundaries are intrinsic to syllable production, and so acquired with syllable structure, or whether they are suprasyllabic, and so acquired in phrasal contexts. Twenty preschool children (aged 3 ; 6 and 4 ; 6) produced: (1) single words with simple and complex onsets (e.g. nail vs. snail); and (2) two-word phrases with intervocalic consonant sequences and varying boundary locations (e.g. this nail vs. bitty snail). Comparisons between child and adult control productions showed that the durational juncture cue was emergent in the four-year-olds' productions of two-word phrases, but absent elsewhere. In contrast, the allophonic cue was evident even in the three-year-olds' productions of single words. Perceptual judgments showed that age- and type-dependent acoustic differences translated into differences in listener behavior. The differential acquisition of the two juncture cues is discussed with reference to the acquisition of articulatory timing control.