How bilingual language experience shapes the infant lexicon: implications for word learning and lexical access

Thesis

In this thesis, I investigate how the words known by bilingual toddlers affect their learning of new words. I explore phonological and semantic connections both within and between languages. I analyse vocabulary questionnaire data collected via parent report for bilingual and monolingual toddlers growing up in the UK. Firstly, I show that while bilinguals’ English vocabulary size lags behind that of monolinguals, conceptual vocabulary size is similar across groups. Notably, when words across both languages are added together, bilinguals understand many more words compared to monolinguals. Bilinguals’ vocabularies include words with the same meaning across languages (translation equivalents). I found that if a word is known in one language (e.g., English "dog"), they have a high likelihood of also learning its translation equivalent (i.e., Spanish "perro"). Additionally, the acquisition of translation equivalents may be supported by systematicity between phonology and meaning. Even monolingual adults are able to make use of cross-linguistic similarity to guess the meaning of unfamiliar foreign words. I show that bilingual toddlers learn cognates (translation equivalents with phonological overlap) earlier than non-cognates, suggesting that toddlers can make use of cross-linguistic similarity to support word learning. Toddlers also display sensitivity to semantic connections in their language(s). Using semantic network analyses, I show that high frequency words and words that have a large number of associative connections to other words are learnt earlier by toddlers than words with low frequency and few connections to other words. The words within a toddlers’ lexicon also have dense connectivity with each other, much more than would be expected if associative patterns in the learning environment had no impact on word acquisition order. Findings from this thesis highlight how bilingual toddlers can capitalise on phonological and semantic connections between words to facilitate learning two languages in parallel.

Authors: Siow, S

• DOI: 10.5287/ora-bmq24xjqe
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: infant research; cognates; bilingualism; vocabulary questionnaire; language development
• Subjects: Psychology; Child development