Language acquisition in the longitudinal BabyRhythm cohort

The Cambridge UK BabyRhythm project is a study of 122 infants as they age from 2 – 30 months, investigating cortical tracking and sensorimotor synchronisation to acoustic and visual rhythm in relation to language acquisition. As there are few standardised language tasks appropriate for this age range, the BabyRhythm project adapted a range of parent-report and infant-led experimental measures that could be used within a home testing environment. Here we present a rich description of infant performance on tasks intended to sample 5 linguistic domains: semantics, phonology, grammar, rhythmic timing and gesture. For each task we describe infant performance (mean, median, range), and we also report performance by sex (N female = 57) and by monolingual (N=92) versus multilingual (N=30) home environments. We report relations between measures. We share our unique longitudinal database (all data available on OSF), and ‘lessons learned’ on adapting language assessments for very young children. Critically, we identify the most reliable language tasks that will be utilised in our subsequent longitudinal brain-behaviour analyses, providing the benchmark upon which future neural and behavioural markers will be measured.