Using a data-driven qualitative approach and drawing from language socialization and communities of practice theories, this dissertation study examines the second language (L2) identity-building strategies of 22 American learners of Russian who engaged in a six-week telecollaborative project with Russian native speakers in two genres of Internet-mediated communication: in one-on-one interactions with an assigned native Russian speaking keypal and in selected virtual communities populated predominantly by native Russian speakers. The investigation of L2 identity enactment in Internet-mediated environments was guided by three research questions pertaining to (1) the nature of the discourse Russian (L2) learners use in interactions with native speakers in two genres of online interactions, (2) the discursive manifestations of L2 learner and speaker identity performances in the learners' online discourse; and (3) the learners' perceptions of their online experiences in two genres of online interactions with native-speaking peers. The methods of critical discourse analysis and interpretative phenomenological analysis were employed to examine the Russian learners' online interactional discourse and offline metatalk regarding their online experiences in the two genres. The analysis of the Russian learners' discourse revealed the complex nature of discursive L2 identity enactment as they moved into and out of the frames of language learners to complete class assignments and negotiate their competent L2 speaker positions in conversations with Russian-speaking peers. The findings indicate that the two genres of online interaction evoked distinct participation patterns and interactional practices. In both genres, L2 identity enactment involved three dimensions: the macro-level of global identity categories, the locally assigned identity positionings (e.g., heritage speaker, multilingual speaker), and interactionally negotiated stances and temporary positions that evoked self- or other-initiated L2 learner/speaker identity performances. The author concludes that L2 identity, when enacted in Internet-mediated environments, represents a continuum of L2 learner-speaker performances that rely on the contextual factors of the online encounter, learners' global identity tokens, and the dynamics of power relations in native-nonnative speaker interaction. Performing an L2 identity online is construed as a critical experience of re-evaluating one's association with the target language and transformation into a new kind of socially oriented multilingual subject.

Using both quantitative and qualitative methods of inquiry, this dissertation study undertakes an exploration of the dynamics of the social interaction in discourse co-constructed by pairs of college students in telecollaborative tandem exchanges. Two groups of participants, Mexican learners of English as a foreign language and American learners of Spanish as a foreign language, participated in video-based telecollaborative tandem exchanges where they worked in pairs to discuss topics assigned by their instructors, communicating half the time in Spanish and half in English. According to the principle of reciprocity in tandem learning, the participants switch between the roles of native speaker (NS) expert and non-native speaker (NNS) learner as they invest equal time, effort, and interest in each language part of the chats. Grounded in sociocultural theory (SCT) for second language acquisition (SLA), this study addresses research questions pertaining to (1) the distribution of talk between the members of each pair and between the language parts of the exchange, (2) the distribution of interactional resources deployed by the members of each pair to establish and maintain intersubjectivity and build a relationship, and (3) the individual experiences of participants regarding their positioning in and perspectives of the exchange. Addressing the three research questions allowed the researcher to look at the telecollaborative tandem exchanges from the perspectives of language production, social aspects of interaction, and individual experiences and perspectives to gather a deeper understanding of the tandem context. The analysis of three data sources—survey responses, chat transcripts from one chat of the semester-long telecollaborative tandem project, and post-project participant interviews—shows that the principle of reciprocity posited by tandem theorists as equal time, effort, and interest in each language part underestimates the complexity of the construct as it was created by the participants in the telecollaborative tandem interactions examined in this dissertation study. A mixed methods approach allowed the researcher to deconstruct and reconsider the construct of reciprocity in telecollaborative tandem learning. The telecollaborative tandem exchanges examined in this study were not reciprocal between language parts of the exchange in terms of language production, use of interactional resources, or tandem participant positioning. Instead, they presented complex pair relationships that used language differently in each language part to establish and maintain intersubjectivity, as well as the strong desire of the participants to position themselves and their partners as peers rather than take on the roles assumed to characterize the tandem context; that is, NS as expert and NNS as learner. In accordance with these findings, telecollaborative tandem learning should be approached with an open understanding of the concept of reciprocity in which the participants co-construct their relationship through meaningful social dialogue as peers, rather than through the roles of NS expert and NNS learner. Based on the findings of this study, the expert–learner model of reciprocity may be too rigid and too static for the dynamic context of telecollaborative tandem learning.

This dissertation contributes to an ongoing debate on the types of linguistic features which can be acquired in a second language by looking at the multiple learning challenges related to the ergative case system (the appearance of –ne with the subject) in Hindi-Urdu by classroom learners. Some hypotheses in second language research hold that interpretable features (features which contribute semantic information) can be acquired in a second language, whereas uninterpretable features (features which express grammatical information) cannot be easily acquired, if ever. Additionally, hypotheses in second language processing hold that the second language learners are able to process semantic information but not grammatical information. This dissertation investigates at the acquisition process of second language learners of Hindi-Urdu acquiring the uninterpretable ergative case. In Hindi-Urdu, the subject of a sentence appears with the ergative case marker –ne, when the verb is transitive and in the perfective aspect. In my dissertation, I test the validity of the aforementioned hypotheses and investigate the acquisition and acquisitional process of ergative case in L2 Hindi-Urdu by L1 English speakers by analyzing data collected by using an acceptability/grammaticality judgement task, a self-paced reading task and a production task from Hindi-Urdu learners and native speakers.

Advances in digital technology have recently allowed for richer text annotation in combination with authentic second language video media. As a result, many educational researchers are focusing increased attention on the effect this application of technology can have on second language acquisition. This study examines the comparative effectiveness of target vocabulary treatments with either native language (L1) definitions or target language (L2) definitions when target vocabulary is presented in either kana or kanji as a part of the subtitles of an L2 film based on participant performance on vocabulary assessments. This study also examines the participants' perceived levels of helpfulness of the varying word treatments. The results of the study suggest that providing annotations for target words in the L2 increases learning of that word more than L1 annotations for intermediate learners of Japanese. On the other hand, learners rated access to definitions in L1 as more helpful than L2 definitions, and they expressed their preference for understanding the story more than learning the target vocabulary.

L'absence de système d'évaluation de la prosodie de l'anglais L2 parlé par des apprenants francophones a motivé la réalisation de ce travail de thèse. Dès lors, l'analyse de facteurs rythmiques dans la production d'apprenants français, qui fait l'objet de cette recherche, a un double objectif : analyser l'influence du rythme de la langue maternelle (L1=français) sur la langue cible (L2=anglais), et d'autre part, proposer des critères évaluatifs du rythme des productions des francophones, à partir de différentes métriques rythmiques proposées dans la littérature. Ces travaux ont mené à l'élaboration d'une base de données d'anglais L1/L2 nommée ANGLISH, à partir de laquelle nous avons montré une discrimination des locuteurs natifs/non natifs s'appuyant sur la combinaison de paramètres rythmiques. Les résultats de ces travaux de recherche montrent donc qu'il est possible de distinguer la L1 de la L2, et de donner une tendance rythmique des productions des apprenants francophones.

<p>La presente investigación estudia el uso adverbial como un tipo de variación léxica en un grupo de aprendientes suecos de español L2 en Chile. Así, nos preguntamos si la cantidad de años de input e interacción con hablantes nativos ejerce alguna influencia en la capacidad del aprendiente de usar el mismo tipo de adverbios, y con la misma frecuencia, que los hablantes nativos. Para eso extrajimos los 10 adverbios más usados en ambos grupos para observar si habían diferencias entre el grupo de aprendientes y el grupo de nativos, recurrimos a la variable tiempo de estadía con el fin de ver si ésta podía explicar el comportamiento de los aprendientes. La hipótesis que formulamos postula que cuanto más años de estadía en el ámbito L2, cuanto más nativo será el empleo adverbial. Los resultados extraídos con el t-test indican que en 8 casos las diferencias del uso adverbial en ambos grupos no resultaron ser significativas, mientras que en 2 casos (donde y abajo) las diferencias sí son significativas. Con la ayuda del test correlacional Pearson observamos si era posible establecer una correlación entre el tiempo de estadía en el ámbito L2 y el uso de estos 2 adverbios, por parte de los aprendientes. Los resultados indicaron que no se puede establecer una correlación entre ambas variables. Luego nos decidimos por analizar la variable nivel de escolarización en la L2 con el uso de estos 2 adverbios. Aquí, los resultados indican que únicamente se puede establecer una correlación en el caso del adverbio abajo.</p>

<p>Learning a second language is different from learning our first one. A lot of rules from the first language, concerning e.g. grammar, intonation and phonology, are so firmly rooted within learners that they will transfer them to the new language regardless of whether they are correct or not. Studies show that the way we are tuned in to the sounds of our first language can make it difficult for us to perceive the phonemes of a new language correctly. In order to study the relationship between Swedish speakers’ faulty production of English vowels and their perception of them, ten subjects participated in a perception test to find out how well they could distinguish between minimal pairs containing phonemes that Swedes often have problems pronouncing correctly. They were also recorded while reading sentences containing the same minimal pairs. The results from the perception test were compared to graphs showing how consistent the subjects were in their pronunciation of these phonemes. The study shows that although some phonemes proved to be more difficult for the subjects to perceive a difference between, a faulty production of these sounds cannot be explained by misperception alone.</p>

<p>Viruses modulate biosynthetic machineries of the host cell for a rapid and efficient virus replication. One important way of modulating protein activity in eukaryotic cells is by reversible phosphorylation. In this thesis we have studied adenovirus and vaccinia virus, two DNA viruses with different replication stategies. Adenovirus replicates and assembles new virions in the nucleus, requiring the host cell transcription and splicing machinieries, whereas vaccinia virus replicates in the cytoplasm, only requiring the cellular translation machinery for its replication. </p><p>Adenovirus uses alternative RNA splicing to produce its proteins. We have shown that adenovirus takes over the cellular splicing machinery by modulating the activity of the essential cellular SR family of splicing factors. Vaccinia virus, that does not use RNA splicing, was shown to completely inactivate SR proteins as splicing regulatory factors. SR proteins are highly phosphorylated, a modification which is important for their activity as regulators of cellular pre-mRNA splicing. We have found that reversible phosphorylation of SR proteins is one mechanism to regulate alternative RNA splicing. We have demonstrated that adenovirus and vaccinia virus induce SR protein dephosphorylation, which inhibit their activity as splicing repressor and splicing activator proteins. We further showed that the adenovirus E4-ORF4 protein, which binds to the cellular protein phosphatase 2A, induced dephosphorylation of a specific SR protein, ASF/SF2, and that this mechanism was important for regulation of adenovirus alternative RNA splicing.</p><p>Inhibition of cellular pre-mRNA splicing results in a block in nuclear- to cytoplasmic transport of cellular mRNAs, ensuring free access of viral mRNAs to the translation machinery. We propose that SR protein dephosphorylation may be a general viral mechanism by which mammalian viruses take control over host cell gene expression.</p>

<p>Pre-mRNA splicing and alternative pre-mRNA splicing are key regulatory steps controlling geneexpression in higher eukaryotes. The work in this thesis was focused on a characterization of thesignificance of exonic and intronic splicing enhancer elements for pre-mRNA splicing.</p><p>Previous studies have shown that removal of introns with weak and regulated splice sitesrequire a splicing enhancer for activity. Here we extended these studies by demonstrating thattwo "strong" constitutively active introns, the adenovirus 52,55K and the Drosophila Ftzintrons, are absolutely dependent on a downstream splicing enhancer for activity <i>in vitro</i>.</p><p>Two types splicing enhancers were shown to perform redundant functions as activators ofSplicing. Thus, SR protein binding to an exonic splicing enhancer element or U1 snRNP bindingto a downstream 5'splice site independently stimulated upstream intron removal. The datafurther showed that a 5'splice site was more effective and more versatile in activating splicing.Collectively the data suggest that a U1 enhancer is the prototypical enhancer element activatingsplicing of constitutively active introns.</p><p>Adenovirus IIIa pre-mRNA splicing is enhanced more than 200-fold in infected extracts. Themajor enhancer element responsible for this activation was shown to consist of the IIIa branchsite/polypyrimidne tract region. It functions as a Janus element and blocks splicing in extractsfrom uninfected cells while functioning as a splicing enhancer in the context of infected extracts.</p><p>Phosphorylated SR proteins are essential for pre-mRNA splicing. Large amount recombinantSR proteins are needed in splicing studies. A novel expression system was developed to expressphosphorylated, soluble and functionally active ASF/SF2 in <i>E. Coli</i>.</p>

Pre-mRNA splicing and alternative pre-mRNA splicing are key regulatory steps controlling geneexpression in higher eukaryotes. The work in this thesis was focused on a characterization of thesignificance of exonic and intronic splicing enhancer elements for pre-mRNA splicing. Previous studies have shown that removal of introns with weak and regulated splice sitesrequire a splicing enhancer for activity. Here we extended these studies by demonstrating thattwo "strong" constitutively active introns, the adenovirus 52,55K and the Drosophila Ftzintrons, are absolutely dependent on a downstream splicing enhancer for activity in vitro. Two types splicing enhancers were shown to perform redundant functions as activators ofSplicing. Thus, SR protein binding to an exonic splicing enhancer element or U1 snRNP bindingto a downstream 5'splice site independently stimulated upstream intron removal. The datafurther showed that a 5'splice site was more effective and more versatile in activating splicing.Collectively the data suggest that a U1 enhancer is the prototypical enhancer element activatingsplicing of constitutively active introns. Adenovirus IIIa pre-mRNA splicing is enhanced more than 200-fold in infected extracts. Themajor enhancer element responsible for this activation was shown to consist of the IIIa branchsite/polypyrimidne tract region. It functions as a Janus element and blocks splicing in extractsfrom uninfected cells while functioning as a splicing enhancer in the context of infected extracts. Phosphorylated SR proteins are essential for pre-mRNA splicing. Large amount recombinantSR proteins are needed in splicing studies. A novel expression system was developed to expressphosphorylated, soluble and functionally active ASF/SF2 in E. Coli.