No description available.

No description available.

Natural spoken language is full of disfluency. Around 10% of utterances produced in everyday speech contain disfluencies such as repetitions, repairs, filled pauses and other hesitation phenomena. The production of disfluency has generally been attributed to underlying problems in the planning and formulation of upcoming speech. However, it remains an open question to what extent factors known to affect the selection and retrieval of words in isolation influence disfluency production during connected speech, and whether different types of disfluency are associated with difficulties at different stages of production. Previous attempts to answer these questions have largely relied on corpora of unconstrained, spontaneous speech; to date, there has been little direct experimental research that has attempted to manipulate factors that underlie natural disfluency production. This thesis takes a different approach to the study of disfluency production by constraining the likely content and complexity of speakers utterances while maintaining a context of naturalistic, spontaneous speech. This thesis presents evidence from five experiments based on the Network Task (Oomen & Postma, 2001), in addition to two related picture-naming studies. In the Network Task, participants described to a listener the route of a marker as it traverses a visually presented network of pictures connected by one or more paths. The disfluencies of interest in their descriptions were associated with the production of the picture name. The experiments varied the ease with which pictures in the networks could be named by manipulating factors known to affect lexical or pre-lexical processing: lexical access and retrieval were impacted by manipulations of picture-name agreement and the frequency of the dominant picture names, while visual and conceptual processing difficulty was manipulated by blurring pictures and through prior picture familiarisation. The results of these studies indicate that while general production difficulty does reliably increase the likelihood of disfluency, difficulties associated with particular aspects of lexical access and retrieval have dissociable effects on the likelihood of disfluency. Most notably, while the production of function word prolongations demonstrates a close relationship to lexical difficulties relating to the selection and retrieval of picture names, filled pauses tend to occur predominantly at the beginning of utterances, and appear to be primarily associated with message-level planning processes. Picture naming latencies correlated highly with the rates of observed hesitations, establishing that the likelihood of a disfluency could be attributed to the same lexical and pre-lexical processes that result in longer naming times. Moreover, acoustic analyses of a subset of observed disfluencies established that those disfluencies associated with more serious planning difficulties also tended to have longer durations, however they do not reliably relate to longer upcoming delays. Taken together, the results of these studies demonstrate that the elicitation of disfluency is open to explicit manipulation, and that mid-utterance disfluencies are related to difficulties during specific production processes. Moreover, the type of disfluency produced is not arbitrary, but may be related to both the type and location of the problem encountered at the point that speech is suspended. Through the further exploration of these relationships, it may be possible to use disfluency as an effective tool to study online language production processes.

The present study examines the nature of bilingual lexical access using category fluency across five language combinations using 109 healthy speakers of Hindi-English, Kannada-English, Mandarin-English, Spanish-English, and Turkish-English. Participants completed a category fluency task in each of their languages in three main categories (animals, clothing, food), each with two subcategories, as well as a language use questionnaire assessing their proficiency in each of their languages. Multivariate analyses of variance revealed that the average number of correct items named in the category fluency task across the three main categories varied across the different groups for English items only. A series of repeated-measures analyses of covariance revealed that the exposure component that had been extracted from the language use questionnaire using a principal component analysis significantly affected the average number of items named across the three main categories. When the effect of exposure was controlled, the effect of language combination was no longer significant. A regression analysis showed that the relative amount of exposure participants had to each of their languages predicted participants’ relative performance in each language. Additional multivariate analyses of variance found significant differences in the number of correct items named in each main category and subcategory in both English and participants’ other language based on language combination. Overall, these results demonstrate the effects of particular language combinations on bilingual lexical access and provide important insights into the role of proficiency on access.

No description available.

This dissertation addresses an unanswered question in Arabic psycholinguistics. Arabic words are characterized by their nonconcatenative structure, in which a consonantal root that encodes the main semantic content is interleaved with a derivational pattern (called "binyan", pl. "binyanim"), which is typically vocalic but may also contain consonantal elements and contributes grammatical information. The canonical example of the Semitic root and binyan system is the combination of root /ktb/ which denotes the broad semantic sense of "writing" with verbal binyan /CaCaC/ (with Cindicating a root consonant) to form [katab] "he wrote" and with nominal place binyan/maCCaC/ to form [maktab] "office". Although significant work has been done on the psycholinguistic reality of Arabic morphemes by exploring various phonological, morphological and semantic features across numerous experimental modalities in both the visual and auditory domains (Boudelaa and Marslen-Wilson, 2004, 2005, 2011), no study has investigated the roles of base/morpheme frequency and surface/word frequency and their implications for underlying morphological structure in the lexicon of Arabic as has been done for English, Dutch, and Finnish (Baayen et al., 1997; Alegre and Gordon, 1999; New et al., 2004; Taft, 1979, 2004). Competing models of word recognition propose various integrations of morphology. Whole-word models suggest that there are no separate representations for morphemes, and that the co-activation of related words can be attributed to similarity in form and meaning (Norris and McQueen, 2008; Tyler et al., 1988). Decomposition models posit that words are recognized by accessing the words' constituent morphemes (Meunierand Segui, 1999; Taft et al., 1986; Wurm, 2000). Hybrid models incorporate multiple pathways to recognition. Words are either recognized holistically or by their constituent morphemes depending on multiple factors (Balling and Baayen, 2008; Taftand Nguyen-Hoan, 2010; Lopez-Villasenor, 2012). Of most relevance to the current study is the role of the productivity of the words' derivational affixes: words with unproductive affixes are processed holistically whereas words with productive affixes are processed as a function of their morphemes. This dissertation presents results from four auditory lexical decision experiments performed with native Jordanian speakers in Amman, Jordan, and provides evidence that binyan productivity determines whether the frequency of the base morpheme affects the speed of recognition. By manipulating root and word frequency for three binyanim, one more productive and two less productive, I provide evidence that verbs in the productive binyan are fully decomposable during lexical access and verbs in less productive binyanim are recognized holistically. For a more productive binyan, I examine Binyan I of the form /CaCaC/, and two less productive binyanim are Binyan VIII of the form /iCtaCaC/and Binyan X of the form /staCCaC/. These results together support a hybrid model of lexical access in which some words are recognized via decomposition into the morphemes they are composed of, and others are recognized by their whole word form. These results are consistent with those of Balling and Baayen (2008); Taft and Nguyen-Hoan (2010); Bertramet al. (2000), among others, as derivational affix productivity is the deciding factor determining whether a word will be recognized holistically or decomposed during lexical access.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Many persons with aphasia (PWA), who have trouble communicating after a stroke, have difficulty naming objects, frequently producing speech errors. Picture (confrontation) naming tasks are commonly used to assess the presence and/or severity of naming difficulties, but these tests do not adequately capture the underlying cause of impairment. This project addresses the limitations of the standard picture naming paradigm by incorporating the measurement of eye movements, thereby providing a precise estimate of participants’ visual attention during the task. While prior studies have measured eye movements to distractor pictures when a spoken word is presented, to our knowledge no eye tracking studies have examined picture naming with written distractors in aphasia. Using a novel approach, we measured PWA’s and healthy controls’ eye movements as they selected the correct written word corresponding to the picture over other related words (semantically and sound-based distractors). The results of this project seek to: (1) indicate the feasibility of a novel eye tracking paradigm to study both intact and impaired lexical retrieval; (2) provide detailed information about the nature and time course of impaired naming; and (3) yield insight into the relative preservation of semantic and phonological representations in aphasia.

If an individual speaks more than one language, there are always at least two ways of verbalising any thought to be expressed. The bilingual speaker must then have a means of ensuring that their utterances are produced in the desired language. However, prominent models of speech production are based almost exclusively on monolingual considerations and require substantial modification to account for bilingual production. A particularly important feature to be explained is the way bilinguals control the language of speech production: for instance, preventing interference from the unintended language, and switching from one language to another. One recent model draws a parallel between bilinguals??? control of their linguistic system and the control of cognitive tasks more generally. The first two experiments reported in this thesis explore the validity of this model by comparing bilingual language switching with a monolingual switching task, as well as to the broader task-switching literature. Switch costs did not conform to the predictions of the task-set inhibition hypothesis in either experiment, as the ???paradoxical??? asymmetry of switch costs was not replicated and some conditions showed benefits, rather than costs, for switching between languages or tasks. Further experiments combined picture naming with negative priming and semantic competitor priming paradigms to examine the role of inhibitory and competitive processes in bilingual lexical selection. Each experiment was also conducted in a parallel monolingual version. Very little negative priming was evident when speaking the second language, but the effects of interlingual cognate status were pronounced. There were some indications of cross-language competition at the level of lexical selection: participants appeared unable to suppress the irrelevant language, even when doing so would make the task easier. Across all the experiments, there was no evidence for global inhibition of the language-not-in-use during speech production. Overall results were characterised by a remarkable flexibility in the mechanisms of bilingual control. A striking dissociation emerged between the patterns of results for cognate and non-cognate items, which was reflected throughout the series of experiments and implicates qualitative differences in the way these lexical items are represented and interconnected.

The purpose of the present study was to examine working memory (WM) capacity, lexical access and phonological skills in 19 children with cochlear implants (CI) (5;7-13;4 years of age) attending grades 0-2, 4, 5 and 6 and to compare their performance with 56 children with normal hearing. Their performance was also studied in relation to demographic factors. The findings indicate that children with CI had visuospatial WM capacities equivalent to the comparison group. They had lower performance levels on most of the other cognitive tests. Significant differences between the groups were not found in all grades and a number of children with CI performed within 1 SD of the mean of their respective grade-matched comparison group on most of the cognitive measures. The differences between the groups were particularly prominent in tasks of phonological WM. The results are discussed with respect to the effects of cochlear implants on cognitive development.