Monash University

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Bilingualism as first language in the early years of twin girls

posted on 2017-03-22, 01:31 authored by Inggall, Erika
Abstract This study investigates the acquisition of Italian and English by non-identical female twins during the period from birth until three years of age. The focus was to observe how the twins acquired their bilingual skills and how their two languages developed in a context where both same aged children grew up together. This study analyses the synergies that developed between the twins themselves and the adults in their family environment, identifying how the development of their languages responded to the linguistic input received. A qualitative research approach was used with an ethnographic-case study methodology. The mother in her role of participant researcher observed the twins daily in their own environment, recording their linguistic development using both video and written field notes. Observations of their behaviour, interactions, general development, and linguistic productions were noted in the form of diary entries. The video recordings were of their verbal productions and were meticulously transcribed prior to an analysis of their linguistic features. The findings show how the twins acquired their two languages from birth and how these codes developed in the context of the dynamics only possible in the relationship between twins. The findings also show that the two codes developed independently from each other from the onset of speech and that the parents’ adherence to the ‘one parent–one language’ principle was a conditio sine qua non to raise both twins as active users of both Italian and English. The data demonstrate that the language preference of one of the twins, (Zoia), strongly influenced the language production of the other twin (Isabella) in their interactions. This is an interesting outcome, since the language used in their interactions (English) was the one to which they were quantitatively less exposed and the one in which they developed a less rich lexicon. The conclusions show that, for both twins, their language acquisition is similar to many of the documented descriptions of bilingual first language acquisition. The features that diverge from these descriptions include the preference for the twins to use their weakest language in their dyadic interactions due to the strong influence of societal factors, and the understanding that these twins may achieve their full linguistic potential only if an adult is interacting with them individually in a separate environment, since the verbal dominance of one of the twins can potentially be detrimental for the linguistic development of the other twin.


Campus location


Principal supervisor

Margaret Gearon

Additional supervisor 1

Jim Hlavai

Year of Award


Department, School or Centre



Doctor of Philosophy

Degree Type



Faculty of Education