This cluster-randomized controlled study examined dual language learners (DLLs) in Norway who received a book-based language intervention program. About 464 DLLs aged 3-5 years in 123 early childhood classrooms participated in the study. The children were acquiring Norwegian as their second language in preschool and spoke a variety of first…

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…

Vocabulary knowledge was tested in a native (Cantonese-Chinese) and foreign (English) language in 150 twins and 150 singletons aged 6-11 years, matched on age, gender, grade level, nonverbal intelligence, parents' education, family income, and number of siblings and household members. The singletons clearly outperformed the twins on the native…