The present study aims to capture linguistic variation in subject distribution of two typologically similar languages, Greek and Chilean Spanish, considering adult monolingual and bilingual speakers of Greek as a heritage/minority language in Chile. The focus is on null and overt third-person subjects in topic-continuity and topic-shift contexts. Such structures involve the interface between syntax and discourse/pragmatics, a vulnerable domain in bilingualism. Previous research has shown overextension of the scope of the overt subject pronoun in contexts where null subjects are discursively expected (e.g. Tsimpli, Sorace, Heycock & Filiaci 2004). The Interface Hypothesis (IH) (Sorace 2011) was formulated to account for such findings, which obtain even in pairs of two null subject languages (Sorace, Serratrice, Filiaci & Baldo 2009). The key question as to the language-contact effects on subject distribution in pairs of two null subject languages requires further exploration while the combination of Greek and Spanish has been so far understudied. The IH is evaluated with new empirical data from a bilingual situation not studied before. Data from oral narratives and aural pronominal anaphora resolution were elicited from monolinguals and three types of bilinguals, namely first-generation immigrants, heritage speakers and L2 speakers of Greek residing in Chile. The monolingual data revealed differences in the use and interpretation of overt subject pronouns between Greek and Chilean Spanish. The crosslinguistic difference lies in the strong deictic properties of the Greek pronoun compared to its Spanish counterpart; hence differences obtain because of the relative strength of the two pronominal forms. No overextension of the scope of overt pronouns was found in bilinguals, against predictions stemming from the Interface Hypothesis. This may relate to the typological similarity between Greek and Spanish as well as to the nature of the Greek pronoun, which makes its use relatively categorical. Such findings lend support to the Representational account (Tsimpli et al. 2004). On the contrary, null subjects gave rise to optionality presumably due to their complexity, which demands higher degrees of computational efficiency. The Vulnerability Hypothesis (Prada Pérez 2018) may also account for the findings.

The present dissertation investigates grammatical gender representation and processing in Modern Standard Arabic (MSA) as a first (L1) and a second (L2) language. It mainly examines whether L2 can process gender agreement in a native-like manner, and the extent to which L2 processing is influenced by the properties of the L2 speakers’ L1. Additionally, it examines whether L2 gender agreement processing is influenced by noun animacy (animate and inanimate) and word order (verb-subject and subject-verb). A series of experiments using both online and offline techniques were conducted to address these questions. In all of the experiments, gender agreement between verb and nouns was examined. The first series of experiments examined native speakers of MSA (n=49) using a self-paced reading task (SPR), an event-related potential (ERP) experiment, and a grammaticality judgment (GJ) task. Results of these experiments revealed that native speakers were sensitive to grammatical violations. Native speakers showed longer reaction times (RT) in the SPR task, and a P600 effect in the ERP, in responses to sentences with mismatched gender agreement as compared to sentences with matched gender agreement. They also performed at ceiling in the GJ task. The second series of experiments examined L2 speakers of MSA (n=74) using an SPR task, and a GJ task. Both experiments included adult L2 speakers whom were divided into two subgroups, -Gender and +Gender, based on whether or not their L1s has a grammatical gender system. The results of both experiments revealed that both groups were sensitive to gender agreement violations. The L2 speakers showed longer RTs, in the SPR task, in responses to sentences with mismatched gender agreement as compared to sentences with matched gender agreement. No difference was found between the L2 groups in this task. The L2 speakers also performed well in the GJ task, as they were able to correctly identify the grammatical and ungrammatical sentences. Interestingly in this task, the -Gender group outperformed +Gender group, which could be due to proficiency in the L2 as the former group obtained a better score on the proficiency task, or it could be that +Gender group showed negative transfer from their L1s. Based on the results of these two experiments, this dissertation argues that late L2 speakers are not restricted to their L1 grammar, and thus, they are able to acquire gender agreement system of their L2 even if this feature is not instantiated in their L1. The results provide converging evidence for the FTFA rather than FFFH model, as it appears that the -Gender group was able to reset their L1 gender parameter according to the L2 gender values. Although the L2 speakers were advanced, they showed slower RTs than the native speakers in the SPR task, and lower accuracy in the GJT. However, it is possible that they are still in the process of acquiring gender agreement of MSA and have not reached their final stage of acquisition. This is supported by the fact that some L2 speakers from both -Gender and +Gender groups performed as well as native speakers in both SPR and GJ tasks. Regarding the effect of animacy, the L2 speakers had slower RT and lower accuracy on sentences with inanimate nouns than on those with animate ones, which is in line with previous L2 studies (Anton-Medez, 1999; Alarcón, 2009; Gelin, & Bugaiska, 2014). The native speakers, on the other hand, showed no effect of animacy in both SPR task and GJT. Further, no N400 effect was observed as a result of semantic gender agreement violations in the ERP experiment. Finally, the results revealed a potential effect of word order. Both the native and L2 speakers showed longer RTs on VS word order than SV word order in the SPR task. Further the native speakers showed earlier and greater P600 effect on VS word order than SV word order in the ERP. This result suggests that processing gender agreement violation is more complex in the VS word order than in the SV word order due to the inherent asymmetry in the subject-verb agreement system in the two-word orders in MSA.

The aim of this study is to investigate whether blind individuals display cognitive advantages over sighted individuals with regard to second language acquisition. Previous studies from neuropsychology have indicated that this is the case. It has been found that blind L1 speakers can compensate for loss of vision by developing better perceptual and cognitive skills compared to sighted individuals, skills that are highly relevant to language acquisition. These studies do not, however, investigate blind L2 speakers, for whom it is not clear whether these advantages are also found.  In all, 80 adults participated in the study: 40 L2 speakers of Swedish (11 early blind, 9 late blind, 20 sighted, AO<18) and a matching group and subgroups of L1 speakers. These speakers underwent tests on speech perception in noise, accentedness in an L2 and memory functions. The results revealed that L2 speakers are at a great disadvantage perceiving speech in noise compared to L1 speakers, and that there was no advantage associated with blindness. In the L1 speakers group, however, the results revealed that the early blind had advantages compared to the late blind and sighted in white noise, but that both blind groups were more negatively affected by babble noise than the sighted. The results in relation to accentedness in an L2 revealed that there were no advantages associated with blindness. The results further revealed there were no advantages associated with blindness on the episodic memory test. The results did, however, reveal that the early blind performed significantly better than the late blind and sighted on all phonological short-term memory tests and that both the early and late blind were significantly better than the sighted on recognition memory for new words, irrespective of language background. The conclusion is that blindness is associated with advantages in, for example, ability to learn new words and syntax, acquisition rate, ultimate L2 attainment, and language aptitude.

and Key Words The linguistic concept of complexity as a component of the CAF triad is used to describe the complexity of texts, either spoken (transcribed) or written, and to describe speaker advancedness not only in L1, but also in L2 research. On the most basic level, lexical complexity and syntactic complexity can be distinguished, however, complexity is a multidimensional concept and many different descriptions and operationalisations exist; there is an even wider gap in terms of measuring lexical complexity of L2 oral speech with lexical frequency wordlists as studies on lexical sophistication have yielded inconsistent and sometimes inconclusive results; the majority of studies on lexical sophistication, one of the subdivisions of lexical complexity, have been carried out on written learner production. For this reason, this thesis focuses on measuring lexical complexity in L2 speech with word frequency lists; more specifically, it presumes that C1 speakers would produce more of complex vocabulary (low-frequency vocabulary) than B2 speakers in our sample; this thesis also attempts to correlate word frequency list results with English Vocabulary Profile results and compare the individual speakers. For this analysis 10 B2 and 10 C1 Czech speakers of English were selected from the LINDSEI spoken...