Major
innovations are becoming available for research in language development and
disorders. Among these innovations, recent tools allow naturalistic recording
in children’s homes and automated analysis to facilitate representative
sampling. This study employed all-day recordings during the 2nd year of life
in a child exposed to three languages, using a fully wearable battery-powered
recorder, with automated analysis to locate appropriate time periods for
coding. This method made representative sampling possible and afforded the
opportunity for a case study indicating that language spoken directly to the
child had dramatically more effect on vocabulary learning than audible
language not spoken to the child, as indicated by chi-square analyses of the
child’s verbal output and input in each of the languages. The work provides
perspective on the role of learning words by overhearing in childhood and
suggests the value of representative naturalistic sampling as a means of
research on vocabulary acquisition.
