Cross-linguistic Influence in L3 Acquisition of English by Persian Heritage Speakers in Norway

Aims and objectives: This thesis investigates cross-linguistic influence (CLI) in child third language (L3) acquisition. The main objectives are to find the source of CLI, whether it is L1, L2, or both, and to find out whether CLI occurs on a property-by-property basis or as a wholesale phenomenon. Methodology: Persian-Norwegian heritage bilinguals acquiring L3 English are compared to L2 English learners with either L1 Persian or L1 Norwegian (matched in English proficiency). The participants were tested through a self-paced reading task and an acceptability judgment task in five language properties: adjective placement (Adj-N), definiteness and gender (where English is similar to Norwegian) subject-verb word order in non-subject-initial declaratives (SV), and adverb-verb (Adv-V) word order in subject-initial declaratives (where English is similar to Persian) Data and analysis: A total of 82 participants were tested in English (L3 learners = 29, L2 learners with L1 Norwegian = 29, L2 learners with L1 Persian = 24). The L3 learners were also tested in their background languages (Persian and Norwegian). Findings: The findings point to a major role of the dominant language (Norwegian), and the analyses showed that age and English proficiency are two significant factors. There was facilitative and non-facilitative CLI from Norwegian in the L3 group. Therefore, the findings do not go against wholesale CLI. While the self-paced reading task did not show any effects of grammaticality or group, there were two critical properties in the acceptability judgement task, definiteness and SV. In definiteness, the L3 group and the Norwegian controls were statistically similar, and they outperformed the Persian control group. In the SV property, however, the Persian controls outperformed the other two groups, while the Norwegian controls and the L3 group were statistically the same again. Significance: This study adds to the existing data on child L3 acquisition and contributes to the ongoing discussions on the role of previously acquired languages, mainly the source and nature of CLI