The thesis explores the implications of Talmy’s typology of motion expression (Talmy 1985, 2000a,b) for bilingual first language acquisition of English (satellite-framing) and French (verb-framing), addressing the following question: How does the expression of motion develop in simultaneous bilingual children in comparison to monolinguals? The particular focus of this study is on the role of crosslinguistic interactions and the extent to which their occurrence and directionality are affected by language-specific properties, children’s age and the factor of task complexity. The thesis pursues two goals. First, it aims to contribute to the growing understanding of the role of languagespecific factors in the acquisition process (e.g. Allen et al. 2007, Choi and Bowerman 1991, Hickmann et al. 2009a). Secondly, by testing various proposals regarding crosslinguistic interactions (Gawliĵek-Maiwald and Tracy 1996, Müller and Hulk 2001, Toribio 2004), it endeavours to shed light on bilingual speech production processes.

Oral event descriptions elicited by means of short video clips from bilingual and monolingual children aged 4 to 10 years are analysed and compared across two production tasks of varying semantic complexity: a simpler voluntary motion task, showing agents performing spontaneous movements along various paths, and a more complex caused motion task, portraying a human agent causing the displacement of various objects in different manners along various paths. Bilinguals’ event descriptions are analysed quantitatively and qualitatively in relation to monolingual English and French control groups across various aspects of verbalisation: (i) the linguistic devices used for information encoding (information packaging), (ii) the number of information components expressed (semantic density), and (iii) their syntactic complexity and compactness (utterance architecture).

The results indicate both parallels and differences to monolingual performance patterns. Although bilinguals’ event descriptions generally follow the typological tendencies characterising monolinguals’ English and French verbalisation tendencies, they also exhibit significant departures from the monolingual range in both languages, at all tested ages and in both production tasks. However, these differences are most prominent in children’s French and in the caused motion task. In this context, bilinguals display a striking preference for satellite-framing encoding options, resulting both in the overuse of crosslinguistically overlapping packaging strategies and in qualitatively idiosyncratic extensions of French locative satellites. Syntactically, bilinguals show a strong tendency to use compact and simple structures (lacking subordination) compared to French monolinguals. An unexpected finding concerns the occurrence of a number of divergent production phenomena that are shared by bilinguals’ productions in both languages and tasks, and suggest a bilingual-specific pattern of use.

The findings are discussed in the context of recent proposals regarding crosslinguistic interactions in simultaneous bilingualism. The persistence of bilingual-specific effects even at age 10 suggests that cross-linguistic interactions characterise bilinguals’ verbal behaviour throughout language development. This supports the notion that the bilingual is a unique speaker-hearer in his own right (Grosjean 1985, 2008). With regard to the impact of typological and general determinants, the findings indicate that bilinguals’ verbalisation choices are guided by a complex interplay of event-specific factors and the perceived overlap of language-specific properties of both languages.