Laboratory observations are a mainstay of language development research, but transcription is costly. We test whether speech recognition technology originally designed for day-long contexts can be usefully applied to this use-case. We compared automated adult word and child vocalization counts from Language Environment Analysis (LENATM) to those of transcribers in 20-minute play sessions with Spanish-speaking dyads (n = 104) at 1;7 and 2;2. For adult words, results indicated moderate associations but large absolute differences. Associations for child vocalizations were weaker with larger absolute discrepancies. LENA has moderate potential to ease the burden of transcription in some research and clinical applications.

Valid indigenous language assessments are needed to further our understanding of how children learn language around the world. We assessed the psychometric properties and performance of two caregiver-report measures of Wolof language skill (language milestones achieved and vocabulary knowledge) for 500 children (ages 0;4 to 2;6) living in rural Senegal. Item response models (IRM) evaluated instrument- and item-level performance and differential function by gender. Both caregiver-report measures had good psychometric properties and displayed expected age and socioeconomic effects. Modest concurrent validity was found by comparing the caregiver-report scores to transcribed child language samples from a naturalistic play session. The caregiver-report method offers a valid alternative to more costly tools, such as direct behavioral assessments or language sampling, for measuring early language development in non-literate, rural African communities. Recommendations are made to further improve the performance of caregiver-report measures of child language skill in these settings.

Research with monolingual children has shown that early efficiency in real-time word recognition predicts later language and cognitive outcomes. In parallel research with young bilingual children, processing ability and vocabulary size are closely related within each language, although not across the two languages. For children in dual-language environments, one source of variation in patterns of language learning is differences in the degree to which they are exposed to each of their languages. In a longitudinal study of Spanish/English bilingual children observed at 30 and 36 months, we asked whether the relative amount of exposure to Spanish vs. English in daily interactions predicts children's relative efficiency in real-time language processing in each language. Moreover, to what extent does early exposure and speed of lexical comprehension predict later expressive and receptive vocabulary outcomes in Spanish vs. English? Results suggest that processing skill and language experience each promote vocabulary development, but also that experience with a particular language provides opportunities for practice in real-time comprehension in that language, sharpening processing skills that are critical for learning.

Research on the early development of fundamental cognitive and language capacities has focused almost exclusively on infants from middle-class families, excluding children living in poverty who may experience less cognitive stimulation in the first years of life. Ignoring such differences limits our ability to discover the potentially powerful contributions of environmental support to the ontogeny of cognitive and language abilities.

Research using online comprehension measures with monolingual children shows that speed and accuracy of spoken word recognition are correlated with lexical development. Here we examined speech processing efficiency in relation to vocabulary development in bilingual children learning both Spanish and English (n=26 ; 2 ; 6). Between-language associations were weak: vocabulary size in Spanish was uncorrelated with vocabulary in English, and children's facility in online comprehension in Spanish was unrelated to their facility in English. Instead, efficiency of online processing in one language was significantly related to vocabulary size in that language, after controlling for processing speed and vocabulary size in the other language. These links between efficiency of lexical access and vocabulary knowledge in bilinguals parallel those previously reported for Spanish and English monolinguals, suggesting that children's ability to abstract information from the input in building a working lexicon relates fundamentally to mechanisms underlying the construction of language.

This study compares the prosodie modifications in mothers' and fathers' speech to preverbal infants in French, Italian, German, Japanese, British English, and American English. At every stage of data collection and analysis, standardized procedures were used to enhance the comparability across data sets that is essential for valid cross-language comparison of the prosodie features of parental speech. In each of the six language groups, five mothers and five fathers were recorded in semi-structured home observations while speaking to their infant aged 0; 10–1;2 and to an adult. Speech samples were instrumentally analysed to measure seven prosodic parameters: mean fundamental frequency (f0), f0-minimum, f0-maximum, f0-range, f0-variability, utterance duration, and pause duration. Results showed cross-language consistency in the patterns of prosodic modification used in parental speech to infants. Across languages, both mothers and fathers used higher mean-f0, f0-minimum, and f0-maximum, greater f0-variability, shorter utterances, and longer pauses in infant-directed speech than in adult-directed speech. Mothers, but not fathers, used a wider f0-range in speech to infants. American English parents showed the most extreme prosodic modifications, differing from the other language groups in the extent of intonational exaggeration in Speech to infants. These results reveal common patterns in caretaker's use of intonation across languages, which may function developmentally to regulate infant arousal and attention, to communicate affect, and to facilitate speech perception and language comprehension. In addition to providing evidence for possibly universal prosodic features of speech to infants, these results suggest that language-specific variations are also important, and that the findings of the numerous studies of early language input based on American English are not necessarily generalisable to other cultures.

Research on the development of efficiency in spoken language understanding has focused largely on middle-class children learning English. Here we extend this research to Spanish-learning children (n=49; M=2;0; range=1;3–3;1) living in the USA in Latino families from primarily low socioeconomic backgrounds. Children looked at pictures of familiar objects while listening to speech naming one of the objects. Analyses of eye movements revealed developmental increases in the efficiency of speech processing. Older children and children with larger vocabularies were more efficient at processing spoken language as it unfolds in real time, as previously documented with English learners. Children whose mothers had less education tended to be slower and less accurate than children of comparable age and vocabulary size whose mothers had more schooling, consistent with previous findings of slower rates of language learning in children from disadvantaged backgrounds. These results add to the cross-linguistic literature on the development of spoken word recognition and to the study of the impact of socioeconomic status (SES) factors on early language development.