An Analysis of Theta Roles in Aphasic Speakers' Speech
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Repositorio Documental de la Universidad de Valladolid FACULTAD de FILOSOFÍA Y LETRAS DEPARTAMENTO de FILOLOGÍA INGLESA Grado en Estudios Ingleses TRABAJO DE FIN DE GRADO AN ANALYSIS OF THETA ROLES IN APHASIC SPEAKERS’ SPEECH PRODUCTION Andrea Sánchez Cabrejas Tutora: Raquel Fernández Fuertes 2018-2019 ABSTRACT This dissertation is an empirical study on theta role assignment in aphasics’ linguistic production. Its aim is twofold: to address whether aphasics follow specific patterns regarding the form and function of the Determiner Phrases (DPs) that are assigned theta roles, and to know whether theta role assignment is an impaired stage of the speech production process and, if not, which causes deficits on aphasics’ speech production. To this purpose and considering previous empirical studies on aphasics’ language, the use of verb assigned theta roles by one anomic aphasic and one Broca’s aphasic is analysed. Conclusions reached from this analysis reveal that (1) specific patterns in terms of theta role type and DP form and function are followed by anomic and Broca’s aphasics, and that (2) it is confirmed that the theta role assignment process is not altered, and that linguistic deficits come from aphasics’ difficulties in accessing phonological representations of lemmas from their lexicon. Key words: theta roles, speech production, Broca’s aphasia, anomic aphasia. RESUMEN Este Trabajo de Fin de Grado es un estudio empírico sobre la asignación de los papeles temáticos en la producción lingüística de afásicos. El objetivo es determinar, por un lado, si los afásicos siguen patrones específicos considerando la forma y la función de los sintagmas determinantes a los que se les asignan papeles temáticos; y, por otro lado, si el proceso de asignación de papeles temáticos está alterado y la causa de los déficits lingüísticos en afásicos. Para ello, y partiendo de estudios empíricos previos sobre el lenguaje de los afásicos, se analiza el uso de papeles temáticos asignados por verbos de un anómico y de un afásico de Broca. Las conclusiones alcanzadas son: (1) que los anómicos y afásicos de Broca siguen un patrón según el tipo de papel temático y la forma y la función; y (2) que el proceso de asignación de papeles temáticos no está alterado y, los déficits del lenguaje que presentan provienen de las dificultades de los afásicos cuando acceden a las representaciones fonológicas de los lemas en su léxico. Palabras clave: papeles temáticos, producción del lenguaje, afasia de Broca, afasia anómica. CONTENTS 1. Introduction ........................................................................................................................ 1 2. Theoretical background ...................................................................................................... 2 2.1. On aphasia ................................................................................................................... 5 2.1.1. Broca’s aphasia .................................................................................................... 7 2.1.2. Anomic aphasia .................................................................................................... 8 2.2. On theta roles ............................................................................................................ 10 3. Previous empirical studies on aphasics’ language ............................................................ 13 4. Research questions ........................................................................................................... 16 4.1. Question set 1: arguments’ form ............................................................................... 16 4.2. Question set 2: arguments’ function ......................................................................... 17 4.3. Question set 3: theta role assignment ........................................................................ 17 5. Methodology ..................................................................................................................... 18 5.1. Participants ................................................................................................................ 18 5.2. Data selection ............................................................................................................ 19 5.3. Data classification ..................................................................................................... 22 6. Results and discussion ...................................................................................................... 25 6.1. Question set 1: arguments’ form ............................................................................... 26 6.2. Question set 2: arguments’ function ......................................................................... 29 6.3. Question set 3: theta role assignment ........................................................................ 34 7. Conclusions ...................................................................................................................... 36 8. Bibliography ..................................................................................................................... 39 1 1. Introduction Due to different factors and causes, people suffer strokes. Many of the damages associated to the different pathologies affect brain’s left hemisphere, where speech areas are located. When an area in charge of speech is affected by a stroke, speech impairments are produced, as for instance aphasia. Depending on the affected area of the brain, aphasics have specific deficits in speech production and comprehension. Nowadays, aphasic speakers have access to many treatments in order to improve speech production and comprehension. These types of pathologies are more and more studied both to be prevented and to find a solution to their effects. However, most of the studies are produced from a clinical point of view, rather than from a linguistic one. For this reason, the present dissertation contributes as a linguistic study of aphasic speakers’ speech production. The study analyses the speech production of two participants, one Broca’s aphasic and one anomic aphasic. From their speech, the focus of analysis is placed on theta roles which are a semantic-syntactic feature of language. Theta roles have been analysed in terms of the DPs (Determiner Phrases) they are assigned to and both the form and function of these DPs is analysed in order to establish patterns in the aphasic speakers’ production. There are different classifications of theta roles, and the one considered in this study is Haegeman’s (1994). Among the theta roles, the ones the present dissertation will target are those assigned by the verb and assigned to DPs which function as subjects, direct objects and indirect objects. Throughout the analysis of theta roles, this study aims to contribute to previous linguistic studies on aphasics’ speech production. Also, its aim is to check whether aphasics’ theta role assignment is impaired, and if it is not, which stage of speech production is altered for each participant. Universidad de Valladolid Andrea Sánchez Cabrejas 2 For this purpose, the present dissertation is divided into eight sections (apart from the introduction). First, a theoretical background on aphasics and on theta roles is provided. Second, previous empirical works on aphasics’ language has been considered. Third, three sets of research questions according to patterns of (1) form, (2) function, and (3) theta role assignment are presented. This will guide the data analyses. Fourthly, the methodology followed in the present study is presented. This includes the selection of data from one anomic and one Broca’s aphasic from the Fridriksson Corpus of Aphasia Bank (MacWhinney, Fromm, Forbes and Holland, 2011) and the data classification criteria followed. Next, the results of the study are presented and discussed in terms of the research questions. And finally, the conclusions section includes the conclusions reached from the dissertation. The dissertation ends with a bibliography section. To accomplish this study, data have been compiled in a database where they are classified and analysed. This is done on an Excel spreadsheet attached to the dissertation in an electronic file. 2. Theoretical background We call speech to the staged process throughout which we can express our feelings or ideas. To perform a word, as it is a meaningful component of speech, it is necessary to associate it with a lexical concept, a process called conceptual preparation (Levelt, Roelofs and Meyer, 1999). Then, each concept is linked with a word or a so-called lemma. To do that, it is necessary to have a lexical selection throughout which we retrieve a lemma from our lexicon. As our lexicon stores thousands of words, the selection of that lemma depends on the context and on the decision-making process of the speaker (Butterworth, 1994); (Levelt, 1999). When doing this selection, the speaker may retrieve two or three lemmas, and will finally select the most activated one according to the concept and the lemma’s frequency of use. When getting a Universidad de Valladolid Andrea Sánchez Cabrejas 3 lemma, the speaker also retrieves its group of diacritic parameters, which must be set for a proper realization of the word, for example the transitive or intransitive feature of a verb (Levelt et al., 1999). After getting the lemma and its parameters from