Noun and verb acquisition was investigated in three- and five-year-old Italian children by means of picture naming of objects and actions, selected from Druks and Masterson (2000). The aim was to examine the previously reported advantage of nouns compared to verbs. Older children were faster than younger children, and naming latencies were faster for object pictures than for action pictures. For errors, the advantage of objects over actions was greater for younger children. A qualitative analysis of errors was carried out according to a classification derived by Masterson, Druks, and Gallienne (2008). Overall, 25% of the errors reflected a complete lack of knowledge of the names or of the meanings of the pictures. Most errors, however, were likely to be due to a not yet fully developed knowledge of the meaning of words labelling the pictures, or to an incomplete conceptual representation, and this pattern was more marked for action concepts.

Perceptual representations of objects and approximate magnitudes are often invoked as building blocks that children combine to acquire the positive integers. Systems of numerical perception are either assumed to contain the logical foundations of arithmetic innately, or to supply the basis for their induction. I propose an alternative to this framework, and argue that the integers are not learned from perceptual systems, but arise to explain perception. Using cross-linguistic and developmental data, I show that small (~1–4) and large (~5+) numbers arise both historically and in individual children via distinct mechanisms, constituting independent learning problems, neither of which begins with perceptual building blocks. Children first learn small numbers using the same logic that supports other linguistic number marking (e.g. singular/plural). Years later, they infer the logic of counting from the relations between large number words and their roles in blind counting procedures, only incidentally associating number words with approximate magnitudes.

This study investigates preschoolers’ ability to understand and produce novel metonyms. We gave forty-seven children (aged 2;9–5;9) and twenty-seven adults one comprehension task and two elicitation tasks. The first elicitation task investigated their ability to use metonyms as referential shorthands, and the second their willingness to name animates metonymically on the basis of a salient property. Although children were outperformed by adults, even three-year-olds could understand and produce metonyms in certain circumstances. Our results suggest that young children may find it easier to produce a metonym than a more elaborate referential description in certain contexts, and that metonymy may serve as a useful strategy in referring to entities that lack a conventional label. However, metonymy comprehension appeared to decrease with age, with older children tending to choose literal interpretations of some metonyms. This could be a result of growing metalinguistic awareness, which leads children to overemphasize literal meanings.

Both touch and speech independently have been shown to play an important role in infant development. However, little is known about how they may be combined in the input to the child. We examined the use of touch and speech together by having mothers read their 5-month-olds books about body parts and animals. Results suggest that speech+touch multimodal events are characterized by more exaggerated touch and speech cues. Further, our results suggest that maternal touches are aligned with speech and that mothers tend to touch their infants in locations that are congruent with names of body parts. Thus, our results suggest that tactile cues could potentially aid both infant word segmentation and word learning.

This study set out to examine whether shyness, an aversion to novelty and unfamiliar social situations, can affect the processes that underlie early word learning. Twenty-four-month-old children (n =32) were presented with sets of one novel and two familiar objects, and it was found that shyer children were less likely to select a novel object as the referent of a novel label. Furthermore, not-shy children then showed evidence of retaining these novel mappings, but shy children did not. These findings suggest that shy children's aversion to novelty and to the unfamiliar context can impact on their word learning.

Onomatopoeia are frequently identified amongst infants’ earliest words (Menn & Vihman, 2011), yet few authors have considered why this might be, and even fewer have explored this phenomenon empirically. Here we analyze mothers’ production of onomatopoeia in infant-directed speech (IDS) to provide an input-based perspective on these forms. Twelve mothers were recorded interacting with their 8-month-olds; onomatopoeic words (e.g. quack) were compared acoustically with their corresponding conventional words (duck). Onomatopoeia were more salient than conventional words across all features measured: mean pitch, pitch range, word duration, repetition, and pause length. Furthermore, a systematic pattern was observed in the production of onomatopoeia, suggesting a conventionalized approach to mothers’ production of these words in IDS.

Some inconsistency is observed in the results from studies of reading development regarding the role of the syllable in visual word recognition, perhaps due to a disparity between the tasks used. We adopted a word-spotting paradigm, with Spanish children of second grade (mean age: 7 years) and sixth grade (mean age: 11 years). The children were asked to detect one-syllable words that could be found at the beginning of pseudo-words, with the boundary between the word and the remaining letters being manipulated. The end of the embedded word could either match the syllabic boundary (e.g. the word FIN in the pseudo-word FINLO, where the syllable boundary is between N and L) or not (e.g. FINUS, where the syllable boundary is located between I and N). The results showed that children of both grades were faster in the syllabic than the non-syllabic condition, and that the magnitude of this effect was the same regardless of reading ability. The results suggest an early universality in the use of syllables in Spanish, regardless of reading level.

In order to address gaps in the literature surrounding the acquisition of translation equivalents (TEs) in young bilinguals, two experiments were conducted. In Experiment 1, TEs were measured in the expressive vocabularies of thirty-four French–English bilinguals at 1;4, 1;10, and 2;6 using the MacArthur Bates CDI. Children's acquisition of TEs occurred gradually, with more balanced ratios of exposure and vocabulary associated with larger proportions of TEs at each wave. Experiment 2 compared a direct measure of TE comprehension with parent report of the same set of words. Results showed that parents may over-report children's TE comprehension, as our sample of two-year-old French–English bilinguals (n = 20) comprehended fewer TEs on a direct measure of receptive vocabulary than parents reported on the vocabulary checklist. The present study provides an original contribution to the literature on bilingual vocabulary development by employing both a longitudinal design and a direct measure of TE comprehension.

We report three studies (one corpus, two experimental) that investigated the acquisition of relative clauses (RCs) in Finnish-speaking children. Study 1 found that Finnish children's naturalistic exposure to RCs predominantly consists of non-subject relatives (i.e. oblique, object) which typically have inanimate head nouns. Study 2 tested children's comprehension of subject, object, and two types of oblique relatives. No difference was found in the children's performance on different structures, including a lack of previously widely reported asymmetry between subject and object relatives. However, children's comprehension was modulated by animacy of the head referent. Study 3 tested children's production of the same RC structures using sentence repetition. Again we found no subject–object asymmetry. The pattern of results suggested that distributional frequency patterns and the relative complexity of the relativizer contribute to the difficulty associated with particular RC structures.

In order to understand how language abilities emerge in typically and atypically developing infants and toddlers, it is important to embrace complexity in development. In this paper, we describe evidence that early language development is an experience-dependent process, shaped by diverse, interconnected, interdependent developmental mechanisms, processes, and abilities (e.g. statistical learning, sampling, functional specialization, visual attention, social interaction, motor ability). We also present evidence from our studies on neurodevelopmental disorders (e.g. Down syndrome, fragile X syndrome, Williams syndrome) that variations in these factors significantly contribute to language delay. Finally, we discuss how embracing complexity, which involves integrating data from different domains and levels of description across developmental time, may lead to a better understanding of language development and, critically, lead to more effective interventions for cases when language develops atypically.

This study examined the vocabulary development of Norwegian second language (L2) learners with Urdu/Punjabi as their first language (L1) at two time-points from kindergarten to primary school, and compared it to the vocabulary development of monolingual Norwegian children. Using path models, the associations between number of picture books in the home, maternal education, and previous L1 and L2 vocabulary on the development of L2 vocabulary breadth and depth were investigated. The results indicate that despite the weaker vocabulary skills of the L2 sample, the growth trajectories of the L2 learners and the monolingual comparison group did not differ. For the L2 learners, we identified both concurrent and longitudinal predictors of vocabulary: the number of books in the home and the time of introduction of the L2 predicted concurrent vocabulary. L1 vocabulary, number of books in the home, and the time of introduction of the L2 predicted vocabulary growth.

This study compares the use of the variable (q), which is realized as rural [q] and urban [ʔ], in the speech of twenty-two parents and their twenty-one children from the village of Oyoun Al-Wadi in Syria. The study shows that children acquire the general gendered linguistic pattern of the community but do not replicate the linguistic frequencies that exist in their immediate environment. Boys and girls exhibit different linguistic behavior. Boys deviate from the non-local caregivers' proportions and approach men's local linguistic behavior, although their local variant proportions remain lower; girls, even those with local mothers, approach the women's supralocal variant proportions. The study shows that sociolinguistic variation is not acquired from adults from a very early age; it is acquired later in life after accepting and ascertaining the gendered linguistic differences and appropriateness norms.

During communication, hearers try to infer the speaker's intentions to be able to understand what the speaker means. Nevertheless, whether (and how early) preschoolers track their interlocutors' mental states is still a matter of debate. Furthermore, there is disagreement about how children's ability to consult a speaker's belief in communicative contexts relates to their ability to track someone's belief in non-communicative contexts. Here, we study young children's ability to successfully acquire a word from a speaker with a false belief; we also assess the same children's success on a traditional false belief attribution task. We show that the ability to consult the epistemic state of a speaker during word learning develops between the ages of three and five. We also show that false belief understanding in word-learning contexts proceeds similarly to standard belief-attribution contexts when the tasks are equated. Our data offer evidence for the development of mind-reading abilities during language acquisition.

There have been many studies examining the differences between infant-directed speech (IDS) and adult-directed speech (ADS). However, investigations asking whether mothers clarify vowel articulation in IDS have reached equivocal findings. Moreover, it is unclear whether maternal speech clarification has any effect on a child's developing language skills. This study examined vowel clarification in mothers’ IDS at 0;10–11, 1;6, and 2;0, as compared to their vowel production in ADS. Relationships between vowel space, vowel duration, and vowel variability and child language outcomes at two years were also explored. Results show that vowel space and vowel duration tended to be greater in IDS than in ADS, and that one measure of vowel clarity, a mother's vowel space at 1;6, was significantly related to receptive as well as expressive child language outcomes at two years of age.

Infants learning languages with long consonants, or geminates, have been found to ‘overselect’ and ‘overproduce’ these consonants in early words and also to commonly omit the word-initial consonant. A production study with thirty Italian children recorded at 1;3 and 1;9 strongly confirmed both of these tendencies. To test the hypothesis that it is the salience of the medial geminate that detracts attention from the initial consonant we conducted three experiments with 11-month-old Italian infants. We first established baseline word-form recognition for untrained familiar trochaic disyllables and then tested for word-form recognition, separately for words with geminates and singletons, after changing the initial consonant to create nonwords from both familiar and rare forms. Familiar words with geminates were recognized despite the change, words with singletons were not. The findings indicate that a feature occurring later in the word affects initial consonant production and perception, which supports the whole-word phonology model.

To track the course of development in children's fine-grained perception of Mandarin tones, the present study explored how categorical perception (CP) of Mandarin tones emerges along age among 70 four- to seven-year-old children and 16 adults. Prominent discrimination peaks were found for both the child and the adult groups, and they were well aligned with the corresponding identification crossovers. Moreover, six-year-olds showed a much narrower width (i.e. a sharper slope) compared to younger children, and have already acquired adult-like identification competence of Mandarin high-level and mid-rising tones. Although the ability to discriminate within-category tone pairs did not change, the between-category discrimination accuracies were positively correlated with chronological ages among child participants. We assume that the perceptual refinement of Mandarin tones in young children may be driven by an accumulation of perceptual development from the tonal information of the ambient sound input.

While recent studies suggest children can use cross-situational information to learn words, these studies involved minimal referential ambiguity, and the cross-situational evidence overwhelmingly favored a single referent for each word. Here we asked whether 2·5-year-olds could identify a noun's referent when the scene and cross-situational evidence were more ambiguous. Children saw four trials in which a novel word occurred with four novel objects; only one object consistently co-occurred with the word across trials. The frequency of distracter objects varied across conditions. When all distracter referents occurred only once (no-competition), children successfully identified the noun's referent. When a high-probability competitor referent occurred on three trials, children identified the target referent if the competitor was absent on the third trial (short-competition) but not if it was present until the fourth trial (long-competition). This suggests that although 2·5-year-olds’ cross-situational learning scales up to more ambiguous scenes, it is disrupted by high-probability competitor referents.

Recent research indicates that infants can learn novel words equally well through addressed speech as through overhearing two adult experimenters. The current study examined to which extent six-year-old children learn from overhearing opportunities in regular kindergarten classroom practices. Fifty-three children (M age = 5;6) were exposed to a story with twelve novel words in three different conditions. In the Addressed condition, children were directly addressed to listen to the story. In the Overhearing Classroom, the children were assigned to a task within earshot of the children of the Addressed condition. In the Overhearing Two Adults condition, the experimenter told the story to another adult. The results showed that the Addressees learned equally well as the Overhearers of Two Adults. However, in the Overhearing Classroom condition children learned significantly fewer words compared to the two other conditions. Different hypotheses are offered to explain the relative success of overhearing two adults compared to overhearing classroom interactions.

This study reports developmental changes in morphological encoding across late childhood. We examined event-related brain potentials (ERPs) during the silent production of regularly vs. irregularly inflected verb forms (viz. -t vs. -n participles of German) in groups of eight- to ten-year-olds, eleven- to thirteen-year-olds, and adults. The adult data revealed an enhanced (right-frontal) negativity 300–450 ms after cue onset for the (silent) production of -t relative to -n past participle forms (e.g. geplant vs. gehauen ‘planned’ vs. ‘hit’). For the eleven- to thirteen-year-olds, the same enhanced negativity was found, with a more posterior distribution and a longer duration (=300–550 ms). The eight- to ten-year-olds also showed this negativity, again with a posterior distribution, but with a considerably delayed onset (800–1,000 ms). We suggest that this negativity reflects combinatorial processing required for producing -t participles in both children and adults and that the spatial and temporal modulations of this ERP effect across the three participant groups are due to developmental changes of the brain networks involved in processing morphologically complex words.

Children undergo gradual progression in their ability to differentiate correct and incorrect pronunciations of words, a process that is crucial to establishing a native vocabulary. For the most part, the development of mature phonological representations has been researched by investigating children's sensitivity to consonant and vowel variation, with a much lesser focus on lexical tones. The current study investigates sensitivity to lexical tones in word recognition with specific attention to role of perceptual salience. Chinese-speaking preschoolers were presented with familiar words that were correctly pronounced, substituted for a subtle tone variant (Tones 2 and 3), or substituted for a salient tone variant (Tones 1 and 4). Results demonstrated that subtle tone variants were mistakenly perceived as correct pronunciations and only salient tone variants were recognized as mispronunciations. Findings suggest that tone integration follows a more complex developmental course that previously concluded.