Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
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Item SECOND LANGUAGE LEXICAL REPRESENTATION AND PROCESSING OF MANDARIN CHINESE TONES(2018) Pelzl, Eric; DeKeyser, Robert; Second Language Acquisition and Application; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation investigates second language (L2) speech learning challenges by testing advanced L2 Mandarin Chinese learners’ tone and word knowledge. We consider L2 speech learning under the scope of three general hypotheses. (1) The Tone Perception Hypothesis: Tones may be difficult for L2 listeners to perceive auditorily. (2) The Tone Representation Hypothesis: Tones may be difficult for L2 listeners to represent effectively. (3) The Tone Processing Hypothesis: Tones may be difficult for L2 listeners to process efficiently. Experiments 1 and 2 test tone perception and representation using tone identification tasks with monosyllabic and disyllabic stimuli with L1 and advanced L2 Mandarin listeners. Results suggest that both groups are highly accurate in identification of tones on isolated monosyllables; however, L2 learners have some difficulty in disyllabic contexts. This suggests that low-level auditory perception of tones presents L2 learners with persistent long-term challenges. Results also shed light on tone representations, showing that both L1 and L2 listeners are able to form abstract representations of third tone allotones. Experiments 3 and 4 test tone representation and processing through the use of online (behavioral and ERP) and offline measures of tone word recognition. Offline results suggest weaknesses in L2 learners’ long-term memory of tones for specific vocabulary. However, even when we consider only trials for which learners had correct and confident explicit knowledge of tones and words, we still see significant differences in accuracy for rejection of tone compared to vowel nonwords in lexical recognition tasks. Using a lexical decision task, ERP measures in Experiment 3 reveal consistent L1 sensitivity to tones and vowels in isolated word recognition, and individual differences among L2 listeners. While some are sensitive to both tone and vowel mismatches, others are only sensitive to vowels or not at all. Experiment 4 utilized picture cues to test neural responses tied directly to tone and vowel mismatches. Results suggest strong L1 sensitivity to vowel mismatches. No other significant results were found. The final chapter considers how the three hypotheses shed light on the results as a whole, and how they relate to the broader context of L2 speech learning.Item Early Phonological Predictors of Toddler Language Outcomes(2015) Gerhold, Kayla; Bernstein Ratner, Nan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Several studies have explored relationships between children's early phonological development and later language performance. This literature has included a more recent focus on the potential for early vocalization profiles in infancy to predict later language outcomes, including those characterized by delay or disorder. The present study examines phonetic inventories and syllable structure patterns in a large cohort of infants as they relate to expressive language outcomes at 2 years of age. Results suggest that as early as 11 months, phonetic inventory and mean syllable structure level are related to two year expressive language outcomes (MLU, MCDI, and types). If specific patterns of production can be established for a typically-developing population then this will additionally inform clinical decision-making. Possible applications are discussed.Item FROM SOUND TO MEANING: QUANTIFYING CONTEXTUAL EFFECTS IN RESOLUTION OF L2 PHONOLEXICAL AMBIGUITY(2014) Lukianchenko, Anna; Gor, Kira; Second Language Acquisition and Application; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In order to comprehend speech, listeners have to combine low-level phonetic information about the incoming auditory signal with higher-order contextual information. Unlike native listeners, nonnative listeners perceive speech sounds through the prism of their native language, which sometimes results in perceptual ambiguity in their second language. Across four experiments, both behavioral and electrophysiological, this dissertation provides evidence that such perceptual ambiguity causes words to become temporarily indistinguishable. To comprehend meaning, nonnative listeners disambiguate words through accessing their semantic, syntactic and morphological characteristics. Syntactic and semantic cues produce a stronger context effect than morphological cues in both native and nonnative groups. Thus, although nonnative representations may differ in that they may lack phonological specification, the mechanisms associated with the use of higher-order contextual information for meaning resolution in auditory sentence comprehension are essentially the same in the native and nonnative languagesItem Statistical Knowledge and Learning in Phonology(2013) Dunbar, Ewan; Idsardi, William J; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis deals with the theory of the phonetic component of grammar in a formal probabilistic inference framework: (1) it has been recognized since the beginning of generative phonology that some language-specific phonetic implementation is actually context-dependent, and thus it can be said that there are gradient "phonetic processes" in grammar in addition to categorical "phonological processes." However, no explicit theory has been developed to characterize these processes. Meanwhile, (2) it is understood that language acquisition and perception are both really informed guesswork: the result of both types of inference can be reasonably thought to be a less-than-perfect committment, with multiple candidate grammars or parses considered and each associated with some degree of credence. Previous research has used probability theory to formalize these inferences in implemented computational models, especially in phonetics and phonology. In this role, computational models serve to demonstrate the existence of working learning/per- ception/parsing systems assuming a faithful implementation of one particular theory of human language, and are not intended to adjudicate whether that theory is correct. The current thesis (1) develops a theory of the phonetic component of grammar and how it relates to the greater phonological system and (2) uses a formal Bayesian treatment of learning to evaluate this theory of the phonological architecture and for making predictions about how the resulting grammars will be organized. The coarse description of the consequence for linguistic theory is that the processes we think of as "allophonic" are actually language-specific, gradient phonetic processes, assigned to the phonetic component of grammar; strict allophones have no representation in the output of the categorical phonological grammar.Item A Voxel Based Approach to Identifying Lesion Sites in Aphasia: Comprehension and Production Deficits in Syntax, Semantics and Phonology(2007-08-20) Kling, Therese Danielle; Shah, Yasmeen; Braun, Allen; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The cortical regions of the brain traditionally associated with deficits of production and comprehension in language are Broca's and Wernicke's areas. Recent evidence suggests that other brain regions are involved and may be specific to linguistic areas of syntax, semantics and phonology. This paper describes the MRI results and language scores of 31 left hemisphere stroke patients with aphasia. Patients' lesions obtained from these MRI scans were reconstructed onto templates and entered into a voxel-based analysis program called Analysis of Brain lesion (ABLe) (Solomon, Raymont, Braun, Butman & Grafman, 2007) along with language scores. The results provided evidence for five key neuroanatomical regions of interest. These include the insula, the planum temporale, the operculum, the temporoparietal occipital (TPO) junction and the putamen. The results revealed common as well as unique areas of brain lesion for each of the behaviors.