Adapting language development research paradigms to online testing: Data from preferential looking, word learning and vocabulary assessment in toddlers.

During the recent pandemic, it became necessary to adapt lab-based studies to online experiments. To investigate the impact of online testing on the quality of data, we focus on three paradigms widely used in infant research: a word recognition task using the Intermodal Preferential Looking Paradigm, a word learning task using the Switch task, and a language assessment tool (WinG) where children identify a target word amongst a set of picture cards. Our results for synchronous and asynchronous studies provide support for the robustness of online testing. In Experiment 1, robust word recognition was found in 24-month-old toddlers. In Experiment 2, 17-month-old infants consistently learned a new word. Finally, Experiment 3 demonstrated that 19- to 26-month-old children performed well on a language assessment test administered online. Overall, effect sizes or language scores were found to be higher than in lab-based studies. These experiments point to promising possibilities for reaching out to families around the world.

Comparing child word associations to adult associative norms: Evidence for child-specific associations with a strong priming effect in 3-year-olds.

Investigating how infants first establish relationships between words is a necessary step towards understanding how an interconnected network of semantic relationships develops in the adult lexical-semantic system. Stimuli selection for these child studies is critical since words must be both familiar and highly imageable. However, there has been a reliance on adult word association norms to inform stimuli selection in English infant studies to date, as no resource currently exists for child-specific word associations. We present three experiments that explore the strength of word-word relationships in 3-year-olds. Experiment 1 collected children's word associations (WA) (N = 150; female = 84, L1 = British English) and compared them to adult associative norms (Moss & Older, 1996; Nelson et al., 2004 (Behavior Research Methods, Instruments, & Computers, 36(3), 402-407)). Experiment 2 replicated WAs from Experiment 1 in an online adaptation of the task (N = 24: 13 female, L1 = British English). Both experiments indicated a high proportion of child-specific WAs not represented in adult norms (Moss & Older, 1996; Nelson et al., 2004 (Behavior Research Methods, Instruments, & Computers, 36(3), 402-407)). Experiment 3 tested noun-noun WAs from these responses in an online semantic priming study (N = 40: 19 female, L1 = British English) and found that association type modulated priming (F(2.57, 100.1) = 13.13, p <. 0001, generalized η2 = .19). This research presents a resource of child-specific imageable noun-noun word pair stimuli suitable for testing young children in word recognition and semantic priming studies.

Vowels and consonants matter equally to British English-learning 11-month-olds' familiar word form recognition.

While adult studies show that consonants are more important than vowels in lexical processing tasks, the developmental trajectory of this consonant bias varies cross-linguistically. This study tested whether British English-learning 11-month-old infants' recognition of familiar word forms is more reliant on consonants than vowels, as found by Poltrock and Nazzi (2015) in French. After establishing that infants prefer listening to a list of familiar words over pseudowords (Experiment 1), Experiment 2 examined preference for consonant versus vowel mispronunciations of these words. Infants listened to both alterations equally. In Experiment 3, using a simplified version of the task with one familiar word only ('mummy'), infants' preference for its correct pronunciation over a consonant or a vowel change confirmed an equal sensitivity to both alterations. British English-learning infants' word form recognition appears to be equally impacted by consonant and vowel information, providing further evidence that initial lexical processes vary cross-linguistically.

Tracking the associative boost in infancy.

Do words that are both associatively and taxonomically related prime each other in the infant mental lexicon? We explore the impact of these semantic relations in the emerging lexicon. Using the head-turn preference procedure, we show that 18-month-old infants have begun to construct a semantic network of associatively and taxonomically related words, such as dog-cat or apple-cheese. We demonstrate that priming between words is longer-lasting when the relationship is both taxonomic and associative, as opposed to purely taxonomic, reflecting the associative boost reported in the adult priming literature. Our results demonstrate that 18-month-old infants are able to construct a lexical-semantic network based on associative and taxonomic relations between words in the network, and that lexical-semantic links are more robust when they are both associative and taxonomic in character. Furthermore, the manner in which activation is propagated through the emerging lexical-semantic network appears to depend upon the type of semantic relation between words. We argue that 18-month-old infants have a mental lexicon that shares important structural and processing properties with that of the adult system.

Children's scale errors: A by-product of lexical development?

Scale errors occur when young children seriously attempt to perform an action on an object which is impossible due to its size. Children vary substantially in the incidence of scale errors with many factors potentially contributing to these differences, such as age and the type of scale errors. In particular, the evidence for an inverted U-shaped curve of scale errors involving the child's body (i.e., body scale errors), which would point to a developmental stage, is mixed. Here we re-examine how body scale errors vary with age and explore the possibility that these errors would be related to the size and properties of children's lexicon. A large sample of children aged 18-30 months (N = 125) was tested in a scale error elicitation situation. Additionally, parental questionnaires were collected to assess children's receptive and expressive lexicon. Our key findings are that scale errors linearly decrease with age in childhood, and are more likely to be found in early talkers rather than in less advanced ones. This suggests that scale errors do not correspond to a developmental stage, and that one determinant of these errors is the speed of development of the linguistic and conceptual system, as a potential explanation for the individual variability in prevalence.

Children's scale errors are a natural consequence of learning to associate objects with actions: A computational model.

Young children sometimes attempt an action on an object, which is inappropriate because of the object size-they make scale errors. Existing theories suggest that scale errors may result from immaturities in children's action planning system, which might be overpowered by increased complexity of object representations or developing teleofunctional bias. We used computational modelling to emulate children's learning to associate objects with actions and to select appropriate actions, given object shape and size. A computational Developmental Deep Model of Action and Naming (DDMAN) was built on the dual-route theory of action selection, in which actions on objects are selected via a direct (nonsemantic or visual) route or an indirect (semantic) route. As in case of children, DDMAN produced scale errors: the number of errors was high at the beginning of training and decreased linearly but did not disappear completely. Inspection of emerging object-action associations revealed that these were coarsely organized by shape, hence leading DDMAN to initially select actions based on shape rather than size. With experience, DDMAN gradually learned to use size in addition to shape when selecting actions. Overall, our simulations demonstrate that children's scale errors are a natural consequence of learning to associate objects with actions.

I: INTRODUCTION.

The majority of the world's children grow up learning two or more languages. The study of early bilingualism is central to current psycholinguistics, offering insights into issues such as transfer and interference in development. From an applied perspective, it poses a universal challenge to language assessment practices throughout childhood, as typically developing bilingual children usually underperform relative to monolingual norms when assessed in one language only. We measured vocabulary with Communicative Development Inventories for 372 24-month-old toddlers learning British English and one Additional Language out of a diverse set of 13 (Bengali, Cantonese, Dutch, French, German, Greek, Hindi-Urdu, Italian, Mandarin, Polish, Portuguese, Spanish, and Welsh). We furthered theoretical understanding of bilingual development by showing, for the first time, that linguistic distance between the child's two languages predicts vocabulary outcome, with phonological overlap related to expressive vocabulary, and word order typology and morphological complexity related to receptive vocabulary, in the Additional Language. Our study also has crucial clinical implications: we have developed the first bilingual norms for expressive and receptive vocabulary for 24-month-olds learning British English and an Additional Language. These norms were derived from factors identified as uniquely predicting CDI vocabulary measures: the relative amount of English versus the Additional Language in child-directed input and parental overheard speech, and infant gender. The resulting UKBTAT tool was able to accurately predict the English vocabulary of an additional group of 58 bilinguals learning an Additional Language outside our target range. This offers a pragmatic method for the assessment of children in the majority language when no tool exists in the Additional Language. Our findings also suggest that the effect of linguistic distance might extend beyond bilinguals' acquisition of early vocabulary to encompass broader cognitive processes, and could constitute a key factor in the study of the debated bilingual advantage.

Infants' First Words are not Phonetically Specified: Own Name Recognition in British English-Learning 5-Month-Olds.

By the end of their first year of life, infants' representations of familiar words contain phonetic detail; yet little is known about the nature of these representations at the very beginning of word learning. Bouchon et al. () showed that French-learning 5-month-olds could detect a vowel change in their own name and not a consonant change, but also that infants reacted to the acoustic distance between vowels. Here, we tested British English-learning 5-month-olds in a similar study to examine whether the acoustic/phonological characteristics of the native language shape the nature of the acoustic/phonetic cues that infants pay attention to. In the first experiment, British English-learning infants failed to recognize their own name compared to a mispronunciation of initial consonant (e.g., Molly versus Nolly) or vowel (e.g., April versus Ipril). Yet in the second experiment, they did so when the contrasted name was phonetically dissimilar (e.g., Sophie versus Amber). Differences in phoneme category (stops versus continuants) between the correct consonant versus the incorrect one significantly predicted infants' own name recognition in the first experiment. Altogether, these data suggest that infants might enter into a phonetic mode of processing through different paths depending on the acoustic characteristics of their native language.

Call me Alix, not Elix: vowels are more important than consonants in own-name recognition at 5 months.

Consonants and vowels differ acoustically and articulatorily, but also functionally: Consonants are more relevant for lexical processing, and vowels for prosodic/syntactic processing. These functional biases could be powerful bootstrapping mechanisms for learning language, but their developmental origin remains unclear. The relative importance of consonants and vowels at the onset of lexical acquisition was assessed in French-learning 5-month-olds by testing sensitivity to minimal phonetic changes in their own name. Infants' reactions to mispronunciations revealed sensitivity to vowel but not consonant changes. Vowels were also more salient (on duration and intensity) but less distinct (on spectrally based measures) than consonants. Lastly, vowel (but not consonant) mispronunciation detection was modulated by acoustic factors, in particular spectrally based distance. These results establish that consonant changes do not affect lexical recognition at 5 months, while vowel changes do; the consonant bias observed later in development does not emerge until after 5 months through additional language exposure.

Monodialectal and multidialectal infants' representation of familiar words.

Monolingual infants are typically studied as a homogenous group and compared to bilingual infants. This study looks further into two subgroups of monolingual infants, monodialectal and multidialectal, to identify the effects of dialect-related variation on the phonological representation of words. Using an Intermodal Preferential Looking task, the detection of mispronunciations in familiar words was compared in infants aged 1;8 exposed to consistent (monodialectal) or variable (multidialectal) pronunciations of words in their daily input. Only monodialectal infants detected the mispronunciations whereas multidialectal infants looked longer at the target following naming whether the label was correctly produced or not. This suggests that variable phonological input in the form of dialect variation impacts the degree of specificity of lexical representations in early infancy.

Implicit meaning in 18-month-old toddlers.

A substantial body of evidence demonstrates that infants understand the meaning of spoken words from as early as 6 months. Yet little is known about their ability to do so in the absence of any visual referent, which would offer diagnostic evidence for an adult-like, symbolic interpretation of words and their use in language mediated thought. We used the head-turn preference procedure to examine whether infants can generate implicit meanings from word forms alone as early as 18 months of age, and whether they are sensitive to meaningful relationships between words. In one condition, toddlers were presented with lists of words taken from the same taxonomic category (e.g. animals or body parts). In a second condition, words taken from two other categories (e.g. clothes and food items) were interleaved within the same list. Listening times were found to be longer in the related-category condition than in the mixed-category condition, suggesting that infants extract the meaning of spoken words and are sensitive to the semantic relatedness between these words. Our results show that infants have begun to construct the rudiments of a semantic system based on taxonomic relations even before they enter a period of accelerated vocabulary growth.

How much exposure to English is necessary for a bilingual toddler to perform like a monolingual peer in language tests?

BACKGROUND: Bilingual children are under-referred due to an ostensible expectation that they lag behind their monolingual peers in their English acquisition. The recommendations of the Royal College of Speech and Language Therapists (RCSLT) state that bilingual children should be assessed in both the languages known by the children. However, despite these recommendations, a majority of speech and language professionals report that they assess bilingual children only in English as bilingual children come from a wide array of language backgrounds and standardized language measures are not available for the majority of these. Moreover, even when such measures do exist, they are not tailored for bilingual children. AIMS: It was asked whether a cut-off exists in the proportion of exposure to English at which one should expect a bilingual toddler to perform as well as a monolingual on a test standardized for monolingual English-speaking children. METHODS & PROCEDURES: Thirty-five bilingual 2;6-year-olds exposed to British English plus an additional language and 36 British monolingual toddlers were assessed on the auditory component of the Preschool Language Scale, British Picture Vocabulary Scale and an object-naming measure. All parents completed the Oxford Communicative Development Inventory (Oxford CDI) and an exposure questionnaire that assessed the proportion of English in the language input. Where the CDI existed in the bilingual's additional language, these data were also collected. OUTCOMES & RESULTS: Hierarchical regression analyses found the proportion of exposure to English to be the main predictor of the performance of bilingual toddlers. Bilingual toddlers who received 60% exposure to English or more performed like their monolingual peers on all measures. K-means cluster analyses and Levene variance tests confirmed the estimated English exposure cut-off at 60% for all language measures. Finally, for one additional language for which we had multiple participants, additional language CDI production scores were significantly inversely related to the amount of exposure to English. CONCLUSIONS & IMPLICATIONS: Typically developing 2;6-year-olds who are bilingual in English and an additional language and who hear English 60% of the time or more, perform equivalently to their typically developing monolingual peers.

English-learning one- to two-year-olds do not show a consonant bias in word learning.

Following the proposal that consonants are more involved than vowels in coding the lexicon (Nespor, Peña & Mehler, 2003), an early lexical consonant bias was found from age 1;2 in French but an equal sensitivity to consonants and vowels from 1;0 to 2;0 in English. As different tasks were used in French and English, we sought to clarify this ambiguity by using an interactive word-learning study similar to that used in French, with British-English-learning toddlers aged 1;4 and 1;11. Children were taught two CVC labels differing on either a consonant or vowel and tested on their pairing of a third object named with one of the previously taught labels, or part of them. In concert with previous research on British-English toddlers, our results provided no evidence of a general consonant bias. The language-specific mechanisms explaining the differential status for consonants and vowels in lexical development are discussed.

Promoting early language development in the Arab world and Sustainable Development Goals 3, 4, 10 and 17.

PURPOSE: This commentary describes a multi-national project which addresses gaps in the design and delivery of health and education services in Arabic-speaking countries in relation to early language development, with a focus on Egypt, Jordan, Lebanon and the Palestinian Territories. This includes: (1) co-production with early years professionals and NGOs of approaches to support early language development; (2) development and standardisation of tools to identify monolingual and multilingual Arabic-speaking children at risk of poor language development; and (3) examination of language development in refugee communities. RESULT: The importance of inter-professional partnership and the inclusion of families in planning support for oral language development is highlighted. Arabic versions of the Communicative Development Inventory (CDI) Toddler were developed, and data collected from 1074 Egyptian, Jordanian and Palestinian monolingual infants aged 8-30 months. Data from 201 age-matched Palestinian infants in Lebanese refugee camps highlight inequalities resulting from limited maternal educational opportunities. Data from 230 multilingual Lebanese 2-year-olds enable the interpretation of CDI scores as a function of language exposure. CONCLUSION: This work contributes to the promotion of robust language development for all Arabic-speaking children. This commentary focusses on sustainable development goal (SDG) 3, SDG 4, SDG 10 and SDG 17.

Lexical stress and phonetic processing in word learning in 20- to 24-month-old English-learning children.

To investigate the interaction between segmental and supra-segmental stress-related information in early word learning, two experiments were conducted with 20- to 24-month-old English-learning children. In an adaptation of the object categorization study designed by Nazzi and Gopnik (2001), children were presented with pairs of novel objects whose labels differed by their initial consonant (Experiment 1) or their medial consonant (Experiment 2). Words were produced with a stress initial (trochaic) or a stress final (iambic) pattern. In both experiments successful word learning was established when the to-be-remembered contrast was embedded in a stressed syllable, but not when embedded in unstressed syllables. This was independent of the overall word pattern, trochaic or iambic, or the location of the phonemic contrast, word-initial or -medial. Results are discussed in light of the use of phonetic information in early lexical acquisition, highlighting the role of lexical stress and ambisyllabicity in early word processing.

Infants' Discrimination of Familiar and Unfamiliar Accents in Speech.

This study investigates infants' discrimination abilities for familiar and unfamiliar regional English accents. Using a variation of the head-turn preference procedure, 5-month-old infants demonstrated that they were able to distinguish between their own South-West English accent and an unfamiliar Welsh English accent. However, this distinction was not seen when two unfamiliar accents (Welsh English and Scottish English) were presented to the infants, indicating they had not acquired the general ability to distinguish between regional varieties, but only the distinction between their home accent and unfamiliar regional variations. This ability was also confirmed with 7-month-olds, challenging recent claims that infants lose their sensitivity to dialects at around that age. Taken together, our results argue in favor of an early sensitivity to the intonation system of languages, and to the early learning of accent-specific intonation and potentially segmental patterns. Implications for the development of accent normalization abilities are discussed.