Introduction: Bilingual children may have smaller vocabulary size (lexical breadth) in one of their languages, or even in both, compared to their monolingual peers [1,2,3]. However, there is less awareness of the bilingual lexical representations, or richness of word knowledge (semantic depth). This study explores how intervention in the home and school languages might modulate the extent and nature of Cross Linguistic Influence (CLI). We examined the effects of a vocabulary intervention in each language separately to determine whether there was CLI of lexical and semantic knowledge.
Methods: Twenty-five English-Hebrew bilingual children (ages 5-6) were tested with a bilingual adaptation of the Story Champs narrative intervention program [4]. Vocabulary instruction was delivered in blocks of English and Hebrew. Different words were targeted in each language, but the children were tested on target words in both languages. Vocabulary knowledge was assessed with a definition task four times throughout the study. The influence of proficiency and age at baseline on the extent of CLI was examined.
Results: Children showed growth in lexical breadth after intervention in each language with CLI, evident in words that were not introduced in the tested language. Moreover, the improvement was not only in the number of items defined but also in the quality of the definitions, indicating CLI in semantic depth. Items that were introduced in one language were sometimes defined better in the other language.
Discussion: Bilingual vocabulary intervention may enhance the breadth and depth of children’s home and school languages. CLI was observed, as instruction in one’s home language increased the depth of lexical knowledge in the school language, and vice versa. Support of the home language did not hinder the development of the school language, and was efficacious in stimulating growth in school language knowledge due to CLI.