Strong similarities observed between babbling and first words suggest a universal foundation of word production in children. The aim of this work was to evaluate the role of biomechanical constraints on babbling and first words production in two children acquiring Tashlhiyt, a Berber language spoken in Morocco. When considering isolated sounds and syllable types, our data provided evidence for a universal basis for early vocal patterns. The subjects produced more stops, more coronals and labials, vowels preferentially belonging to the lower left part of the vowel space, and open syllables. However, they only partially confirmed the existence of the preferred CV combinations generally observed in the early production of children learning various languages. The comparison between babbling and first words revealed a linguistic continuity between the two periods but also some increasing complexity and diversification in the words, which can be explained by an increase of articulatory capacities.

The goal of this study is to provide crosslinguistic data on the acquisition of phonetic complexity among children acquiring four different languages: Tunisian Arabic, Tashlhiyt Berber, English, and French. Using an adaptation of Jakielski's (2000) Index of Phonetic Complexity (IPC), we carried out an analysis to assess phonetic complexity of children's early vocabulary in the four languages. Four different samples from each language were analyzed: 50 words selected from an adult dictionary of each language, 50 words from child-directed speech, 50 words targeted by the child, and the child's actual pronunciations of those 50 words. Globally, we hypothesized that children's early productions would be shaped by universal articulatory constraints, but also by the language they are exposed to, depending on its phonological complexity. Our findings show that Arabic displays higher degrees of complexity compared to Berber, English and French, and that children acquiring Arabic target and produce more complex words than children learning Berber, English and French.

Some researchers have suggested that young children choose to say mainly words containing sounds they can produce and avoid words with sounds they find difficult to produce. This proposed pattern of ‘selection’ supports a hypothesis of dominance of phonological factors in words children choose to say. Based on longitudinal spontaneous data samples during their first 50 word period, word-based tokens produced by two English and two French monolingual children were analyzed. Token frequencies in spontaneously produced word targets (SW-T) were compared to children's actual productions (SW-A) of those target words to understand relationships between targets children choose to say and their patterns in actual productions, (i.e., to evaluate the presence of ‘selection’). Place of articulation (i.e., labial, coronal and dorsal) in initial word position within CV, CVC, and CVCV word forms was compared. Analysis of spontaneous output in daily interactions in children learning two languages with differing phonological systems enables a more general evaluation of issues related to the interface of phonological and lexical aspects during the earliest period of language acquisition.

In this article, we address relations between lexical and phonological development, with an emphasis on the notion of phonological contrast. We begin with an overview of the literature on word learning and on infant speech perception. Among other results, we report on studies showing that toddlers’ perceptual abilities do not correlate with the development of phonological contrasts within their lexicons. We then engage in a systematic comparison between the lexical development of two child learners of English and their acquisition of consonants in syllable onsets. We establish a developmental timeline for each child's onset consonant system, which we compare to the types of phonological contrasts that are present in their expressive vocabularies at each relevant milestone. Like the earlier studies, ours also fails to return tangible parallels between the two areas of development. The data instead suggest that patterns of phonological development are best described in terms of the segmental categories they involve, in relative independence from measures of contrastiveness within the learners’ lexicons.

As children learn language, they spontaneously imitate the speech of those around them. This article investigates the new words that five children imitated between 1 and 2 years of age. Children were more likely to imitate new words as they aged and as their productive language developed. After controlling for age, children also were more likely to imitate new words that were shorter and with high neighborhood densities, and that contained sounds the children had previously produced accurately. Together, the findings demonstrate that both the patterns of the target words and children's productive abilities are predictors of children's imitative speech. This supports models of language development where there are influences stemming not only from phonological and lexical representations, but also from phonetic representations.

Quantity and quality of input affect language development, but input features also depend on the context of language emission. Previous research has described mother-child interactions and their impact on language development according to activity types like mealtimes, book reading, and free play. Nevertheless, few studies have sought to quantify activity types in naturalistic datasets including less-studied languages and cultures. Our research questions are the following: we ask whether regularities emerge in the distribution of activity types across languages and recordings, and whether activities have an impact on mothers' linguistic productions. We analyse input for two children per language, at three developmental levels. We distinguish three activity types: solitary, social and maintenance activities, and measure mothers' linguistic productions within each type. Video-recorded activities differ across families and developmental levels. Linguistic features of child-directed speech (CDS) also vary across activities – notably for measures of diversity and complexity – which points to complex interactions between activity and language.

Naturalistic data are a useful source for language acquisition research. Recently, the emphasis has been placed on using denser corpora, in order to capture a more accurate picture of child language development. However, working with large amounts of data raises resource issues, since it is time-consuming to record and to transcribe. In this article, I focus on what would be the ideal duration of a naturalistic recording for it to be considered a representative enough sample of children's linguistic behaviours to observe the acquisition of words and sounds. Some of the results suggest that 30 minutes of recording may be enough to capture these specific developments, but these results are discussed in the perspective of what an ideal session could be.