When bilingual children use one language, they may be influenced by their knowledge of their other language. While such cross-linguistic influence is known to occur in children at the morpho-syntactic level, lexical effects have mostly been studied in bilingual adults. It is unclear to what extent bilingual children’s two languages also influence each other at the lexical level. This thesis therefore aims to uncover the internal structure of the bilingual child’s lexicon and the processes that may lead to lexical cross-linguistic influence. In doing so, it also examines the role of various individual-level, task- and context-level, and language-level factors in the way lexical cross-linguistic influence may emerge.
Based on a series of experiments involving a variety of word comprehension and production tasks, this thesis concludes that, like bilingual adults, bilingual children have an integrated lexicon which is accessed in a language-nonselective manner. This means that words from both languages are represented in one shared system and that these representations can become (co-)activated irrespective of the language they belong to, depending on word form and meaning properties. For example, translation equivalents can become co-activated through shared meaning representations, resulting in lexical priming effects or, if they also overlap in form, cognate facilitation effects. The degree of co-activation also depends on children’s language dominance, with dominant-language words typically being more readily activated. Furthermore, the strength and manner in which effects of lexical cross-linguistic influence manifest were found to be modulated by a complex interplay between language dominance, task demands, language context, and language distance.
