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Purpose This study introduces a framework to produce very short versions of the MacArthur–Bates Communicative Development Inventories (CDIs) by combining the Bayesian-inspired approach introduced by Mayor and Mani (2019) with an item response theory–based computerized adaptive testing that adapts to the ability of each child, in line with Makransky et al. (2016). Method We evaluated the performance of our approach—dynamically selecting maximally informative words from the CDI and combining parental response with prior vocabulary data—by conducting real-data simulations using four CDI versions having varying sample sizes on Wordbank—the online repository of digitalized CDIs: American English (a very large data set), Danish (a large data set), Beijing Mandarin (a medium-sized data set), and Italian (a small data set). Results Real-data simulations revealed that correlations exceeding .95 with full CDI administrations were reached with as few as 15 test items, with high levels of reliability, even when languages (e.g., Italian) possessed few digitalized administrations on Wordbank. Conclusions The current approach establishes a generic framework that produces very short (less than 20 items) adaptive early vocabulary assessments—hence considerably reducing their administration time. This approach appears to be robust even when CDIs have smaller samples in online repositories, for example, with around 50 samples per month-age.

The relative ease of children’s learning of nouns vs. verbs can be explained by the characteristics of linguistic input. In Korean, syntactic structures contain parameters adversarial for learning nouns such as the SOV word-order, in which noun appears utterance-medially, and frequent elision of noun. Nevertheless, Korean children readily learn nouns and even show a noun-bias in production. We investigate two strategies Korean mothers adopt to aid children’s noun learning: adapting the default word-order to place nouns in the utterance-final position, and presenting the nouns in repetition. In Study 1, we examined the distribution of nouns in Korean and English child-directed speech (CDS) and found that Korean mothers scramble the word-order to [(S)VO] or repeat the noun at the end of the utterance [(S)OV, O], which we term tag-repetition, especially when the children were younger. These patterns were rarely found in English-speaking mothers’ speech. They also presented nouns in isolation with a higher rate than English, particularly to youngest children. To test whether the Korean mothers’ adaptation of word-order and repetition is specific to CDS, we compared the rate of word-order adaptation and lexical repetition of nouns in Korean CDS and adult-directed speech (ADS). The results showed that in spontaneous speech, Korean mothers place nouns on the edges and employed tag repetition more frequently in CDS than in ADS. The findings suggest that mothers might have a tacit knowledge of the importance of utterance-final position and syntactic constraints, and adapt their language to address the language-specific constraints in the input.

Early vocabularies typically contain more nouns than verbs. Yet, the strength of this noun-bias varies across languages and cultures. Two main theories have aimed at explaining such variations; either that the relative importance of nouns vs. verbs is specific to the language itself, or that extra-linguistic factors shape early vocabulary structures. To address this debate, the present study compares the relative distribution of verbs and nouns within the same language-English-between Malay-English and Mandarin-English bilingual infants and toddlers. The English receptive lexicons of Mandarin-English bilingual children contained more verbs than those of Malay-English bilinguals, suggesting that the nounbias is modulated by factors external to English. We discuss the potential role of socio-cultural differences on the composition of children early vocabularies.

The present study explores the viability of using tablets in assessing early word comprehension by means of a two-alternative forced-choice task. Forty-nine 18-20-month-old Norwegian toddlers performed a touch-based word recognition task, in which they were prompted to identify the labelled target out of two displayed items on a touchscreen tablet. In each trial, the distractor item was either semantically related (e.g., dog-cat) or unrelated (e.g., dog-airplane) to the target. Our results show that toddlers as young as 18 months can engage meaningfully with a tablet-based assessment, with minimal verbal instruction and child–administrator interaction. Toddlers performed better in the semantically unrelated condition than in the related condition, suggesting that their word representations are still semantically coarse at this age. Furthermore, parental reports of comprehension, using the Norwegian version of the MacArthur Bates Communicative Development Inventories, predicted toddlers’ performance, with parent-child agreement stronger in the semantically unrelated condition, suggesting that parents declare a word to be known by their child if it is understood at a coarse representational level. This study provides among the earliest evidence that remote data collection in infants before their second birthday is viable, as comparable results were observed from both in-lab and online administration of the touch-screen recognition task.