Research concerning structure and processing in the mental lexicon has achieved central prominence within cognitive psychology and psycholinguistics. Historically, however, much of the research on the lexicon focussed not on its role in language comprehension, but as a medium for studying semantic memory. This picture has changed in recent years, with much more research examining the role of lexical processes and output in language comprehension. Gathered together in this volume is the work of some of those researchers who are responsible for this shift of emphasis. Chapters deal with the role of sentence contexts in word recognition, processes involved in the activation and enhancement of lexical information, and the interaction of lexical and syntactic information in sentence processing. A wide range of theoretical and empirical issues relating to language understanding are discussed.

Sets out state-of-the-art methodological and theoretical advancements to shed light on how bilingual speakers comprehend ambiguous information.

The most frequently used words in English are highly ambiguous; for example, Webster's Ninth New Collegiate Dictionary lists 94 meanings for the word "run" as a verb alone. Yet people rarely notice this ambiguity. Solving this puzzle has commanded the efforts of cognitive scientists for many years. The solution most often identified is "context": we use the context of utterance to determine the proper meanings of words and sentences. The problem then becomes specifying the nature of context and how it interacts with the rest of an understanding system. The difficulty becomes especially apparent in the attempt to write a computer program to understand natural language. Lexical ambiguity resolution (LAR), then, is one of the central problems in natural language and computational semantics research. A collection of the best research on LAR available, this volume offers eighteen original papers by leading scientists. Part I, Computer Models, describes nine attempts to discover the processes necessary for disambiguation by implementing programs to do the job. Part II, Empirical Studies, goes into the laboratory setting to examine the nature of the human disambiguation mechanism and the structure of ambiguity itself. A primary goal of this volume is to propose a cognitive science perspective arising out of the conjunction of work and approaches from neuropsychology, psycholinguistics, and artificial intelligence--thereby encouraging a closer cooperation and collaboration among these fields. Lexical Ambiguity Resolution is a valuable and accessible source book for students and cognitive scientists in AI, psycholinguistics, neuropsychology, or theoretical linguistics.

Though Broca's aphasia is traditionally defined as an expressive language impairment, listeners with Broca's aphasia (LWBA) typically evince sentence comprehension deficits as well. These comprehension deficits are characterized by difficulty understanding certain types of sentences that contain complex syntax. While some research proposes that the source of the comprehension disorder can be attributed to a syntactic processing delay, other research argues that syntactic processing impairments are secondary to primary lexical processing impairments. The Delayed Lexical Activation Hypothesis (DLA) suggests that a slowed lexical activation system results in lexical information "feeding" syntactic processing too slowly, leading to a mismatch between processing rate and what is required for fast-acting processing routines. A series of three studies with LWBA are presented to explore (a) if the DLA holds in the face of simple, canonically ordered sentences (Chapter 3), and (b) if lexical access delays can be mitigated through manipulations of speech input rate (Chapter 4) and/or cue based prediction (Chapter 5). Chapter 2 reviews current research with LWBA and details prior empirical evidence supporting the presence of a processing delay in both lexical and syntactic processing. Chapter 3 presents evidence of real-time lexical access during processing of syntactically simple sentences. Results showed LWBA demonstrated a pattern of protracted lexical access as compared to unimpaired controls. Chapter 4 explores if slowed input rate would combine with the purported slowed lexical activation to yield 'on-time' lexical access patterns. While a LWBA group effect of rate was not found, interesting patterns emerged when considering individual patterns of brain damage. It was found that the proportion of damage to a brain region of interest implicated in lexical, but not syntactic processing, significantly predicted the effect of rate of speech on the time-course of lexical access. Finally, Chapter 5 investigates if LWBA demonstrate predictive processing by showing 'on-time' access with contextual cues that unimpaired listeners have been shown to use - biased adjectives. LWBA were able to use semantic, not structural, cues to mitigate a lexical access delay. These results taken together support the DLA hypothesis; that a lexical access delay underlies the comprehension disorder in LWBA.