Word learning in bilingual English-Italian toddlers

The aim of the proposed project is to study how children initially learn the sound pattern and meaning of a word ('lexical configuration') and then associate that word with those they already know ('Lexical engagement'). This study will focus on bilingual toddlers learning Italian and English in nursery school settings. While it is commonly agreed that the two separately accessible lexical systems regularly interact in bilingual adults (Kroll et al., 2006), this issue is still debated with respect to children (Vihman, 2014). Particularly relevant to this study are Vihman's findings (2016), where bilingual children consistently drew on both languages to generalise word patterns and enlarge their lexicon. Therefore, investigating lexical engagement in bilingual toddlers could offer new insights both on lexical engagement and on the single/double system issue. According to Leach and Samuel (2007), in order to fully acquire a new word, both lexical configuration and lexical engagement have to be achieved. The latter usually takes much longer to emerge than the former, since it requires consolidation of the newly learned words entry. Previous research on (monolingual) adults (Dumay & Gaskell, 2012) and older children (Henderson et al., 2012) has shown that such consolidation can be enhanced by sleep, eventually leading to lexical engagement. However, lexical engagement has seldom if ever been investigated in very young children, whether learning one or two languages. Investigating these issues within the nursery school setting will allow me to make a contribution to educational planning and processes.

In this study I will investigate word learning in bilingual toddlers aged 2 and 3 years, exposed to both Italian and English. The research questions are as follows:
1. What evidence can be found of lexical engagement in the course of word learning in toddlers?
2. Does sleep enhance children's ability to achieve lexical engagement of newly learned word forms?
3. Does lexical competition in bilingual children straddle languages, so that engagement reflects associations between words from the two different lexicons?
4. Is cross-linguistic lexical competition affected by the amount of exposure children have to each of their languages?
5. How is lexical engagement affected by educational practices in the Italian and in English nursery school settings?

I will recruit toddlers in bilingual pre-schools in both Italy and the UK (N = 20 in each location), where the relative amount of experience with (or exposure to) each language is expected to differ. I have already identified 2 such pre-schools in each country, and believe this to be a realistic sample size. An English monolingual control group of the same age will also be recruited. Lexical configuration will be tested through a nonword repetition task such as the one used in Keren-Portnoy et al. (2010) and a pause detection task, while lexical engagement through a preferential looking task. Note that the experimental technique of pause detection, which was designed by Mattys (York: See Mattys & Clark, 2002, for experiments with adults; Henderson et al., 2012, 2013 for experiments with older children) has not yet been attempted with younger children, to my knowledge. I will modify the task to make it usable with toddlers, by not requiring an overt judgment, but rather measuring looking time or pupil dilation. Thus, my study will also make contributions to research methodology with very young children. This research will shed light on long-standing issues in bilingualism and early first language acquisition; it will likely also usefully inform early language teaching practices.