Six-month-olds infer object size based on pitch: they map high-pitched vowels onto smaller objects and low-pitched vowels onto larger objects (Peña et al., 2011). The ‘sound symbolism bootstrapping hypothesis’ (Imai & Kita, 2014) proposes that this may support understanding of word-meaning correspondences; by drawing on iconic pairings between linguistic cues and corresponding referents (e.g., higher pitch for smaller objects), infants develop understanding of word-referent associations. Here we analyse mother-child interactions, testing whether sound-symbolic pitch-size correspondences occur in infant-directed speech. 40 dyads engaged in (semi-)naturalistic interaction around picture books containing images of toys of varying sizes. We compare mothers’ pitch when referring to small versus large toys, analysing i) actual size (bigger vs. smaller toys); ii) relative toy size congruence (i.e., congruent vs. incongruent with real-world expectation); and iii) transparency of the test paradigm as regards its focus on size contrastiveness (non-transparent, moderately transparent, highly transparent) to observe the nuances of size sound symbolism in infant-directed speech.

Monomorphemic words have been found to influence category formation, as they encode one general category and thus activate it more than other related categories in the same lexical network. On the other hand, multimorphemic words can encode multiple categories from the same network by the multiple forms they combine. Superordinate categories are encoded by sub-lexical forms (e.g., affixes), while the entire words encode lower categories in the hierarchical structure. In the present study, we asked whether sub-lexical forms influence the learning of the meaning encoded by the entire word they underlie. We used Semitic-like words where sub-lexical forms (syllabic patterns) encode superordinate categories of manner-of-motion, and the entire words encode lower-level categories (moving characters). In our main experiment, a word-learning test showed that a shared syllabic pattern had a negative effect on the learning of the moving characters encoded by the entire word. This effect was revealed mainly in dimensions related to the superordinate category encoded by the pattern. The effect and its direction are beyond the expectations of enhanced category representations suggested in previous literature. We conclude that the effect of word-form is beyond the specific category they encode and can have different directions at different hierarchical levels.

Late talkers (LTs) exhibit delayed vocabulary development, which might stem from a lack of a typical word learning strategy to generalise object labels by shape, called the ‘shape bias’. We investigated whether LTs can acquire a shape bias and whether this accelerates vocabulary learning. Fourteen LTs were randomly allocated to either a shape training group (Mage = 2.76 years, 6 males), which was taught that objects similar in shape have the same name, or a control group (Mage = 2.61 years, 4 males), which was taught real words without any focus on object shape. After seven training sessions, children in the shape training group generalised trained labels by shape (d = 1.28), but not unfamiliar labels. Children in the control group extended all labels randomly. Training did not affect expressive vocabulary.

Second language (L2) learners need to acquire large vocabularies to approach native-like proficiency. Many controlled experiments have investigated the factors facilitating and hindering word learning; however, few studies have validated these findings in real-world learning scenarios. We use data from the language learning app Lingvist to explore how L2 word learning is affected by valence (positivity/negativity) and concreteness of target words and their linguistic contexts. We found that valence, but not concreteness, affects learning. Users learned positive and negative words better than neutral ones. Moreover, positive words are learned best in positive contexts and negative words in more negative contexts. Word and context valence effects are strongest on the learner’s second encounter with the target word and diminish across subsequent encounters. These findings provide support for theories of embodied cognition and the lexical quality hypothesis and point to the linguistic factors that make learning words, and by extension languages, faster.

Prosody includes the pitch, timing and loudness in speech, which can convey meaning and emotion. This study examines whether prosodic categories affect novel noun learning and whether the referent characteristic influence learning. Previous research showed that emotional prosody interfered with adults’ noun learning (West et al., 2017), but it had no effect on children (West et al., 2022). However, these researchers varied their method across ages, including animacy and complexity of the referent, and it is unclear if the results extend beyond the three emotional prosodies tested. Participants in the current set of studies heard novel words presented in five prosodic categories (within-subject) in order to learn the label for either animate or inanimate objects (between-subject). Study 1 compared inanimate objects and aliens, with better noun learning performance for inanimate objects. Study 2 compared inanimate objects with the same objects with faces added, but there was no difference in noun learning by object type. Both studies showed differences in noun learning by the prosodic category, with warning less accurate than naming. These results demonstrate how extralinguistic factors like prosody, attention and referent complexity influence noun learning.

Word-object and action-object learning in children aged 30 to 48 months appears to develop at a similar time scale and adheres to similar attentional constraints. However, children below 36 months show different patterns of learning word-object and action-object associations when this information is presented in a bimodal context (Eiteljoerge et al., 2019b). Here, we investigated 12- and 24-month-olds’ word-object and action-object learning when this information is presented in a unimodal context. Forty 12- and 24-month-olds were presented with two novel objects that were either first associated with a novel label (word learning task) and then later with a novel action (action learning task) or vice versa. In subsequent yoked test phases, children either heard one of the novel labels or saw a hand performing one of the actions presented with the two objects on screen while we measured their target looking. Generalized linear mixed models indicate that 12-month-olds learned action-object associations but not word-object associations and 24-month-olds learned neither word- nor action-object associations. These results extend previous findings (Eiteljoerge et al., 2019b) and, together, suggest that children appear to learn action-object associations early in development while struggling with learning word-object associations in certain contexts until 2 years of age.

During vocabulary instruction, it is important to teach words until their representations are robust enough to be retained. For adults, the number of training sessions a target item is successfully retrieved during training predicts the likelihood of post-training retention. To assess this relationship in children, we reanalyzed data from Gordon et al. (2021b, 2022). Four- to six-year-old children completed six training days with word form-object pairs and were tested one month later. Results indicate that the number of training sessions that a word form was retrieved was positively related to post-training retention. We discuss implications for vocabulary instruction and interventions.

Young children today are exposed to masks on a regular basis. However, there is limited empirical evidence on how masks may affect word learning. The study explored the effect of masks on infants’ abilities to fast-map and generalize new words. Seventy-two Chinese infants (43 males, Mage = 18.26 months) were taught two novel word-object pairs by a speaker with or without a mask. They then heard the words and had to visually identify the correct objects and also generalize words to a different speaker and objects from the same category. Eye-tracking results indicate that infants looked longer at the target regardless of whether a speaker wore a mask. They also looked longer at the speaker’s eyes than at the mouth only when words were taught through a mask. Thus, fast-mapping and generalization occur in both masked and not masked conditions as infants can flexibly access different visual cues during word-learning.

Adults differ in the ease with which they acquire lexical tones in a non-native language. Individual differences have been attributed to several factors, such as the role that pitch plays in a learner's L1 to signal lexical meaning (L1 tonal status), the shape of the tones to be acquired (tone types), as well as extralinguistic factors (such as musical experience and working memory). Here, we ask whether learners from a spectrum of L1 tonal statuses (Dutch, Swedish and Japanese, and Thai) differ in their tone word learning facility, whilst we simultaneously investigate the effects of tone type, and musical experience and working memory. Our findings suggest that above and beyond L1 tonal status, the strongest predictor of tone word learning was pre-lexical tone processing (measured by a tone categorization task), although the strength of the link between pre-lexical and lexical processing may be modulated by L1 tonal status.

How much information do language users need to differentiate potentially absolute synonyms into near-synonyms? How consistent must the information be? We present two simple experiments designed to investigate this. After exposure to two novel verbs, participants generalized them to positive or negative contexts. In Experiment 1, there was a tendency across conditions for the verbs to become differentiated by context, even following inconsistent, random, or neutral information about context during exposure. While a subset of participants matched input probabilities, a high proportion did not. As a consequence, the overall pattern was of growth in differentiation that did not closely track input distributions. Rather, there were two main patterns: When each verb had been presented consistently in a positive or negative context, participants overwhelmingly specialized both verbs in their output. When this was not the case, the verbs tended to become partially differentiated, with one becoming specialized and the other remaining less specialized. Experiment 2 replicated and expanded on Experiment 1 with the addition of a pragmatic judgment task and neutral contexts at test. Its results were consistent with Experiment 1 in supporting the conclusion that quality of input may be more important than quantity in the differentiation of synonyms.

The present study investigated the differential effects of pitched and unpitched musicianship on tone identification and word learning. We recruited 44 Cantonese-pitched musicians, unpitched musicians, and non-musicians. They completed a Thai tone identification task and seven sessions of Thai tone word learning. In the tone identification task, the pitched musicians outperformed the non-musicians but the unpitched musicians did not. In session 1 of the tone word learning task, the three groups showed similar accuracies. In session 7, the pitched musicians outperformed the non-musicians but the unpitched musicians did not. The results indicate that the musical advantage in tone identification and word learning hinges on pitched musicianship. From a theoretical perspective, these findings support the precision element of the OPERA hypothesis. Broadly, they reflect the need to consider the heterogeneity of musicianship when studying music-to-language transfer. Practically, the findings highlight the potential of pitched music training in enhancing tone word learning proficiency. Furthermore, the choice of musical instrument may matter to music-to-language transfer.

While there are well-known demonstrations that children can use distributional information to acquire multiple components of language, the underpinnings of these achievements are unclear. In the current paper, we investigate the potential pre-requisites for a distributional learning model that can explain how children learn their first words. We review existing literature and then present the results of a series of computational simulations with Vector Space Models, a type of distributional semantic model used in Computational Linguistics, which we evaluate against vocabulary acquisition data from children. We focus on nouns and verbs, and we find that: (i) a model with flexibility to adjust for the frequency of events provides a better fit to the human data, (ii) the influence of context words is very local, especially for nouns, and (iii) words that share more contexts with other words are harder to learn.

Meaning comes in different shapes and sizes. Content words like parrot and persimmon and perambulate convey some important – and very specific – kinds of meanings. But the kinds of meaning that syntactic structures encode are of a different sort. They are more general and abstract than those kinds of words, and they are linked to the underlying organization of language. The essential insight behind syntactic bootstrapping is that children can leverage the way that structural elements connect to abstract meanings to help them acquire the more specific kinds of meanings in the content words.

There is a current ‘theory crisis’ in language acquisition research, resulting from fragmentation both at the level of the approaches and the linguistic level studied. We identify a need for integrative approaches that go beyond these limitations, and propose to analyse the strengths and weaknesses of current theoretical approaches of language acquisition. In particular, we advocate that language learning simulations, if they integrate realistic input and multiple levels of language, have the potential to contribute significantly to our understanding of language acquisition. We then review recent results obtained through such language learning simulations. Finally, we propose some guidelines for the community to build better simulations.

Like verbs, adjectives pose a challenge to the young word learner in that some – like red, round, rough, or rectangular – map onto properties that are detectable through the senses, while others – like ready, reasonable, or required – express abstract properties that have no reliable, physical correlate. Even for those adjectives whose properties are observable, how does a child know that one particular property is being highlighted above all others? The physical environment alone will not suffice. Just as with verbs, the child learning adjectives is faced with an inherent indeterminacy of meaning, which can only be resolved through the incorporation of cues originating from multiple sources.

Research shows that infants and preschoolers can learn novel words equally well through addressed speech as through overhearing two adults. However, most of this research draws from samples of ethnic majority children. The current study compares word learning in preschoolers (M age = 5;6) with an ethnic minority and an ethnic majority background (N = 132). An experimenter of the majority group (representative for most teachers in Flemish education) told a story in three different interaction situations: Addressed Speech, Overhearing Classroom and Overhearing Two Adults. Results show that children of both ethnic groups learn novel words in Addressed Speech and in Overhearing Classroom equally well. However, minority children learned significantly fewer words in Overhearing Two Adults. This study suggests important differences in how ethnic majority and minority children learn through indirect speech in educational (monolingual) settings. In addition, the study scrutinizes the potential role of social identification in overhearing mechanisms.

This study examined the effect of a shape cue (i.e., co-speech gesture) on word depth. We taught 23 preschoolers (M = 3;5 years, SD = 5.82) novel objects with either shape (SHP) or indicator (IND) gestures. SHP gestures mimicked object form, but IND gestures were not semantically related to the object (e.g., an upward-facing palm, extended toward the object). Each object had a unique IND or SHP gesture. Outcome measures reflected richer semantic and phonological learning in the SHP than in the IND condition. In the SHP condition, preschoolers (a) expressed more semantic knowledge, (b) said more sounds in names, and (c) generalized more names to untaught objects. There were also fewer disruptions to prime picture names in the SHP condition; we discuss the benefit of a co-speech shape gesture to capitalize on well-established statistical word learning patterns.

The current research examined whether children’s expectations about labeling conventions can be influenced by limited exposure to a foreign language. Three- to four-year-old Korean children were presented with two speakers who each assigned a novel label either in Korean or Spanish to a novel object. Children were asked whether both labels were acceptable for the object. Children who had more exposure to a foreign language through live social interaction, but not through media, were more likely to accept both Korean and Spanish labels. These findings indicate the influence of social interaction in foreign language exposure on children’s understanding of different labeling conventions.