To evaluate which features of spoken language aid infant word learning, a corpus of infant-directed speech (M. R. Brent & J. M. Siskind, 2001) was characterized on several linguistic dimensions and statistically related to the infants' vocabulary outcomes word by word. Comprehension (at 12 and 15 months) and production (15 months) were…

The unique relation of language use (i.e., output) to language growth was investigated for forty-seven 30-month-old Spanish-English bilingual children (27 girls, 20 boys) whose choices of which language to speak resulted in their levels of English output differing from their levels of English input. English expressive vocabularies and receptive…

This study employs the Specificity Principle to examine the relative impacts of external (input quantity at home and at school, number of books and reading frequency at home, teachers' degree and experience, language usage, socioeconomic status) and internal factors (children's working memory, nonverbal intelligence, learning-related…

The mothers of 29 Spanish English bilingual 25-month-olds kept diary records of their children's dual language exposure and provided information on their children's English and Spanish language development using the MacArthur-Bates inventories. Relative amount of exposure predicted language outcomes in English and Spanish. In addition, the number…

This study investigated the relation between teachers' (N = 22) use of sophisticated and complex language in urban middle-school classrooms and their students' (mean age at pretest = 11.51 years; N = 782; 568 language minority and 247 English only) vocabulary knowledge. Using videotaped classroom observations, teachers' speech was transcribed and…