In the beginning was the word: A study of monolingual and bilingual children’s lexicons

All words have inherent properties linked to their form, meaning and usage patterns affecting when they are acquired and how easily they are processed. As languages and cultures differ, words with equivalent meanings may be acquired at different ages across languages. Crosslinguistic research and assessment must take such differences into account; this issue is particularly important for a valid assessment of multilingual children. In addition, children’s language acquisition is influenced by their dispositions and personal preferences as well as their linguistic and sociocultural environment. This dissertation asks how linguistic factors may account for the composition of monolingual and bilingual children’s lexicons, and whether a tool that does take such factors into account can be expected to yield comparable results across different groups of bilinguals. It explores data on lexical development and tests two new assessment tools designed to provide a valid assessment of bilingual children’s language skills; one of these tools is also used to profile the children’s language background (exposure and use). The dissertation documents common patterns as well as cross-linguistic differences in children’s first words. It shows that lexical properties must be taken into account in any linguistic assessment that strives for comparability across languages. Furthermore, it confirms the prominent roles of type and token frequency on the lexicon, and underlines that studies of frequency effects and assessment tools aiming to account for such effects must pay attention to the source of frequency data. It confirms that a new lexical assessment tool that takes into account for lexical properties does yield comparable results across languages. It may however not be sensitive enough to capture early stages of language shift. The results are in accordance with usage-based theories of language and language acquisition. The dissertation contributes with a new measure of lexical development and new knowledge about lexical effects within and across languages