I investigated how bilingual children learn to use the past verb forms available to them in their dual-language input. Past tense forms are particularly relevant to the study of heritage language (HL), as their acquisition depends on various factors, such as the frequency of the form in the input, its functional complexity or discursive salience (Tomasello, 2009; Nicoladis & Paradis, 2012; Parisse et al., 2018). Because bilingual children are often unevenly exposed to their two languages, monolinguals may draw patterns from their more stable input faster than their bilingual peers (Paradis 2010; Paradis et al., 2011). I questioned whether children acquiring French as a HL differed from their French monolingual peers in their paths and rates of acquisition of past morphology.

 I analyzed longitudinal data from two French monolingual children living in Paris and aged between 1;06 and 4;06 (Parisse & Morgenstern, 2012), and two French-English bilingual children living in London and aged between 2;06 and 3;07 (Hervé, 2016). All the children were video-recorded monthly  in interaction with their caregivers. The data was transcribed and coded using the CLAN software. All verb forms were identified and described formally. Past verb forms were further coded as target or non-target (in which case the deviation from target was characterized), and as either contributed by the child to the interaction or reproduced from a previous utterance. 

The results suggest dominance effects on the acquisition  of past morphology by the two bilingual children under study, especially in their HL. Individual differences were linked to language use  - the child who used French more consistently over the period followed the same path of acquisition as the French monolingual children whose productions were analyzed. Crosslinguistic influence accounted for the bilingual children's non-target realizations of French past forms, which differed qualitatively from those observed in the monolingual corpora.

This study supports usage-based theories of language acquisition by confirming that the children's path of acquisition of past morphology was guided by input properties, regardless of language status (majority or HL), but that the quantity of input received impacted the children's rate of acquisition of past verb forms. 

BibliographY

Hervé, C., & Serratrice, L. (2018). The development of determiners in the context of French–English bilingualism: a study of cross-linguistic influence. Journal of child language, 45(3), 767-787.

Nicoladis, E., & Paradis, J. (2012). Acquiring regular and irregular past tense morphemes in English and French: Evidence from bilingual children. Language Learning, 62(1), 170-197.

Paradis, J. (2010). Bilingual children's acquisition of English verb morphology: Effects of 

language exposure, structure complexity, and task type. Language Learning, 60(3), 651-680.

Paradis, J., Nicoladis, E., Martha, C., & Genesee, F. (2011). Bilingual children's acquisition of the past tense: A usage-based approach. Journal of Child Language, 38(03), 554-578.

Parisse, C., de Pontonx, S., & Morgenstern, A. (2018). L'imparfait dans le langage de l'enfant.  Language Interaction and Acquisition, 9(2), 183-225.

Tomasello, M. (2009). Constructing a language. Harvard University Press.