The present thesis investigates in how properties of a reader’s first language (L1) have an influence on syntactic processing in a second language (L2). While the Competition Model (Bates & MacWhinney, 1982, 1987, 1989, MacWhinney, 1997) predicts that syntactic properties of the L1 can have an influence on L2 processing, the Shallow-Structure Account (Clahsen & Felser, 2006) suggests that an L2 speaker’s representation of an L2 sentence is shallower, lacks syntactic detail, and is therefore not detailed enough for properties of the L1 to have an influence on L2 processing (Papadopoulou & Clahsen, 2003). In two sets of studies, I investigate whether L2 speakers of English activate syntactic information from their L1 while processing English sentences. In Experiments 1-4, native speakers of German, and control groups of native speakers of French and English, are confronted with English sentences consisting of a word order which exists in both English and German, but which represents different underlying syntactic structures in both languages. Results suggest that native speakers of German activate syntactic information from their L1 while reading such sentences. Experiments 5-7 represent an attempt to address both the issue of L1 influence and the issue of shallow processing within the context of the same experimental design. Native speakers of German, and a control group of native English speakers, read grammatically incorrect English sentences with a word order which would either be grammatically correct in German, or grammatically incorrect in both English and German. In this set of experiments, we found evidence against an influence of syntactic properties of the L1. Results also suggest that contrary to the predictions of the shallow-structure account, L2 speakers fully parse the syntactic structure of an L2 sentence, and compute detailed syntactic representations.

The present body of research examined adult bilinguals who acquired a second language (L2) from an early age and who subsequently developed language dominance in that language. The question investigated is whether such "early L2-dominant bilinguals" attain a native level of proficiency in their second language. This possibility was explored by comparing bilinguals who had Cantonese L1 (logographic, morphosyllabic), Vietnamese L1 (alphabetic, morphosyllabic) or some "Other" L1 (alphabetic, non-morphosyllabic) to English monolinguals on various tasks in English (L2). The ability to process spoken stimuli was examined using phoneme deletion, spelling-to-dictation, and auditory comprehension tasks. The results showed that bilinguals from all backgrounds had greater difficulty than monolinguals on tasks that required sublexical skills, with the morphosyllabic groups performing the most poorly. The processing of print was investigated using reading aloud and reading comprehension tasks. In contrast to the auditory tasks, only Cantonese L1 bilinguals displayed any discernable difference from monolinguals on reading. Cantonese L1 bilinguals did, however, outperform monolinguals on orthographic memory tasks, such as the spelling of idiosyncratic L2 words. The findings therefore indicated that L1 linguistic structure influences L2 processing in adulthood, despite the former having become subordinate. In order to elucidate whether transfer effects arise solely from early exposure to L1, or whether L1 maintenance also plays a role, the L1 and L2 proficiency of a separate sample of Cantonese L1 bilinguals was examined. However, no meaningful relationship between L1 and L2 proficiency was found. Finally, a sample of late bilinguals were also tested in order to determine whether the L1-specific effects observed in early bilinguals are simply an attenuated version of those in late bilinguals,. The results revealed that the development of language dominance in L2 does lead to qualitatively different outcomes in L2 for early bilinguals. The findings from the present research are most consistent with the Competition Model (e.g., Hernandez, Li, & MacWhinney, 2005), which espouses the notions of L1 transfer and entrenchment to explain second language acquisition. Overall, the research indicates that native attainment in L2 is not assured for all early L2-dominant bilinguals.

The present body of research examined adult bilinguals who acquired a second language (L2) from an early age and who subsequently developed language dominance in that language. The question investigated is whether such "early L2-dominant bilinguals" attain a native level of proficiency in their second language. This possibility was explored by comparing bilinguals who had Cantonese L1 (logographic, morphosyllabic), Vietnamese L1 (alphabetic, morphosyllabic) or some "Other" L1 (alphabetic, non-morphosyllabic) to English monolinguals on various tasks in English (L2). The ability to process spoken stimuli was examined using phoneme deletion, spelling-to-dictation, and auditory comprehension tasks. The results showed that bilinguals from all backgrounds had greater difficulty than monolinguals on tasks that required sublexical skills, with the morphosyllabic groups performing the most poorly. The processing of print was investigated using reading aloud and reading comprehension tasks. In contrast to the auditory tasks, only Cantonese L1 bilinguals displayed any discernable difference from monolinguals on reading. Cantonese L1 bilinguals did, however, outperform monolinguals on orthographic memory tasks, such as the spelling of idiosyncratic L2 words. The findings therefore indicated that L1 linguistic structure influences L2 processing in adulthood, despite the former having become subordinate. In order to elucidate whether transfer effects arise solely from early exposure to L1, or whether L1 maintenance also plays a role, the L1 and L2 proficiency of a separate sample of Cantonese L1 bilinguals was examined. However, no meaningful relationship between L1 and L2 proficiency was found. Finally, a sample of late bilinguals were also tested in order to determine whether the L1-specific effects observed in early bilinguals are simply an attenuated version of those in late bilinguals,. The results revealed that the development of language dominance in L2 does lead to qualitatively different outcomes in L2 for early bilinguals. The findings from the present research are most consistent with the Competition Model (e.g., Hernandez, Li, & MacWhinney, 2005), which espouses the notions of L1 transfer and entrenchment to explain second language acquisition. Overall, the research indicates that native attainment in L2 is not assured for all early L2-dominant bilinguals.

Ob es eine 'kritische Periode' beim Spracherwerb gibt oder nicht, wird kontrovers diskutiert. Die Untersuchung zweisprachiger Probanden mit unterschiedlichem Spracherwerbsalter und Sprachleistungsniveau in der Zweitsprache stellt eine gute Möglichkeit dar, diese Frage näher zu beleuchten. In der vorliegenden Studie nutzten wir die funktionelle Magnetresonanztomographie, um den Einfluss der Faktoren Spracherwerbsalter und Sprachleistungsniveau auf die neuronalen Korrelate grammatikalischer und semantischer Verarbeitungsprozesse bei italienisch-deutschsprachigen Probanden mit unterschiedlichem Spracherwerbsalter und Sprachleistungsniveau zu untersuchen. Während das zerebrale Aktivierungsmuster beim semantischen Urteilen größtenteils vom erreichten Sprachleistungsniveau abhängig war, beeinflusste das Spracherwerbsalter hauptsächlich die zerebrale Repräsentation grammatikalischer Verarbeitungsprozesse. Diese Ergebnisse weisen darauf hin, dass beide, das Spracherwerbsalter und das Sprachleistungsniveau, die neuronalen Substrate der Verarbeitung der Zweitsprache beeinflussen, jedoch mit einem unterschiedlichen Effekt auf grammatikalische und semantische Verarbeitungsprozesse. / The existence of a 'critical period' for language acquisition is still controversial. Bilingual subjects with variable age of acquisition and proficiency level constitute a suitable model to study this issue. In the present study, we used functional magnetic resonance imaging to investigate the effects of age of acquisition and proficiency level on neural correlates of grammatical and semantic judgments in Italian-German bilinguals who learned the second language at different ages and had different proficiency levels. While the pattern of brain activity for semantic judgment was largely dependent on the proficiency level, the age of acquisition mainly affected the cortical representation of grammatical processes. These findings support the view that both age of acquisition and proficiency level affect the neural substrates of second language processing, with a differential effect on grammar and semantics.