The study used naturalistic data on the production of nominal prefixes in the Otopamean language Northern Pame (autonym: Xi'iuy) to test Whole Word (constructivist) and Minimal Word (prosodic) theories for the acquisition of inflection. Whole Word theories assume that children store words in their entirety; Minimal Word theories assume that children produce words as binary feet. Northern Pame uses obligatory portmanteaux prefixes to inflect nouns for class, number, animacy and possessor. Singular nouns constitute 90 percent of the nouns that the children hear and yet all five two-year-old children frequently omitted the singular noun prefixes, but produced the low frequency noun suffixes for dual and animate plural. Neither the children's production of the noun-class prefixes nor their prefix overextensions correlated with the adult type and token frequencies of production. Northern Pame children constructed Minimal Words that contain binary feet and disfavor the production of initial, extrametrical prefixes.

The Cross-linguistic Lexical Task (CLT; Haman, Łuniewska & Pomiechowska, 2015) is a vocabulary task designed to enable cross-linguistic comparisons both across and within (bilingual) children. In this paper we assessed the validity of the CLT as a measure of language proficiency in bilingual children, by determining the extent to which (i) age-matched, monolingual Spanish-speaking and Dutch-speaking children obtained similar scores, (ii) the CLT correlated with other measures of language proficiency in monolingual and bilingual children, and (iii) whether the factors underlying the CLT's construction, i.e., target words’ estimated Age of Acquisition and Complexity Index, were predictive of children's scores. Our results showed that, while the CLT correlated with other measures and is therefore a valid means of tapping into language proficiency, caution is required when using it to compare children's language proficiency cross-linguistically, as scores for Dutch-speaking and Spanish-speaking monolinguals sometimes differed.

The study analysed spectral and tongue shape dynamics of voiceless alveolar and postalveolar fricatives produced by ten children learning Scottish English. Synchronised ultrasound tongue imaging data and acoustic data were used to characterise children's productions of the phonemic contrast. Six children had consistently accurate productions of both fricative targets, with some cross-consonant phonetic differences in the direction previously demonstrated for older children and adults, as well as some immature acoustic and articulatory dynamic patterns. Instrumental analyses made it possible to describe tongue shape for phonemic errors and phonetically distorted realisations. There was some evidence of articulatory contrast in production preceding contrast in perception. The observed patterns can be explained by the complex articulatory demands on the fricative production, in combination with the developing control of articulators. The paper concludes by discussing the implications of the results for phonological theory and for speech therapy practice.

We analysed both structural and functional aspects of sentences containing the four adverbials “after”, “before”, “because”, and “if” in two dense corpora of parent-child interactions from two British English-acquiring children (2;00–4;07). In comparing mothers’ and children's usage we separate out the effects of frequency, cognitive complexity and pragmatics in explaining the course of acquisition of adverbial sentences. We also compare these usage patterns to stimuli used in a range of experimental studies and show how differences may account for some of the difficulties that children have shown in experiments. In addition, we report descriptive data on various aspects of adverbial sentences that have not yet been studied as a resource for future investigations.

Is noun dominance in early lexical acquisition a widespread or a language-specific phenomenon? Thirty Singaporean bilingual English–Mandarin learning toddlers and their mothers were observed in a mother-child play interaction. For both English and Mandarin, toddlers’ speech and reported vocabulary contained more nouns than verbs across book reading and toy playing. In contrast, their mothers’ speech contained more verbs than nouns in both English and Mandarin but differed depending on the context of the interaction. Although toddlers demonstrated a noun bias for both languages, the noun bias was more pronounced in English than in Mandarin. Together, these findings support early noun dominance as a widespread phenomenon in the lexical acquisition debate but also provide evidence that language specificity also plays a minor role in children's early lexical development.

Children's differing learning trajectories cross-linguistically have been at the forefront of gender acquisition research, often with conflicting results and conclusions. As a result, the source of children's different learning behaviors in gender acquisition has been unclear. I argue that children's gender acquisition is driven by the search for productive patterns. First, I provide corpus studies where the predictions of a learning model (Yang, 2016) are formulated. Second, I report the results of an elicited production task on Icelandic-speaking children (N = 26, ages 2;6-6;3 years) and adults (N = 18) that puts these predictions to test. The results suggest that Icelandic-speaking children and adults draw a categorical distinction between productive and unproductive suffixes in Icelandic gender assignment. I discuss the implications of these findings for morphological learning beyond gender acquisition.

The functions of acoustic-phonetic modifications in infant-directed speech (IDS) remain a question: do they specifically serve to facilitate language learning via enhanced phonemic contrasts (the hyperarticulation hypothesis) or primarily to improve communication via prosodic exaggeration (the prosodic hypothesis)? The study of lexical tones provides a unique opportunity to shed light on this, as lexical tones are phonemically contrastive, yet their primary cue, pitch, is also a prosodic cue. This study investigated Cantonese IDS and found increased intra-talker variation of lexical tones, which more likely posed a challenge to rather than facilitated phonetic learning. Although tonal space was expanded which could facilitate phonetic learning, its expansion was a function of overall intonational modifications. Similar findings were observed in speech to pets who should not benefit from larger phonemic distinction. We conclude that lexical-tone adjustments in IDS mainly serve to broadly enhance communication rather than specifically increase phonemic contrast for learners.

While voicing contrasts in word-onset position are acquired relatively early, much less is known about how and when they are acquired in word-coda position, where accurate production of these contrasts is also critical for distinguishing words (e.g., dog vs. dock). This study examined how the acoustic cues to coda voicing contrasts are realized in the speech of 4-year-old Australian English-speaking children. The results showed that children used similar acoustic cues to those of adults, including longer vowel duration and more frequent voice bar for voiced stops, and longer closure and burst durations for voiceless stops along with more frequent irregular pitch periods. This suggests that 4-year-olds have acquired productive use of the acoustic cues to coda voicing contrasts, though implementations are not yet fully adult-like. The findings have implications for understanding the development of phonological contrasts in populations for whom these may be challenging, such as children with hearing loss.

This study examined the roles of parental gender and context in the communicative functions of parents’ child-directed speech. Seventy three families with toddlers participated in the study. Dyadic and triadic parent-toddler interactions were videotaped during structured play activities. Results indicated context-dependent variability in parents’ facilitative speech and gentle guidance. Parental gender effects were observed in parents’ directive speech but no gender or contextual effects were observed in parents’ referential speech. Results suggest the need for a closer examination of parental gender and contextual factors related to parents’ speech functions.