We report on an English-speaking, aphasic individual (TB) who showed a striking dissociation in speaking with the different forms (allomorphs) that an inflection can take. Although very accurate in producing the consonantal inflections (-/s/, -/z/, -/d/, -/t/), TB consistently omitted syllabic inflections (-/əz/, -/əd/), therefore correctly saying "dogs" or "walked," but "bench" for benches or "skate" for skated. Results from control tests ruled out that TB's selective difficulties stemmed from problems in selecting the correct inflection for the syntactic context or problems related to phonological or articulatory mechanisms. TB's selective difficulties appeared instead to concern morpho-phonological mechanisms responsible for adapting morphological elements to word phonology. These mechanisms determine whether the plural inflection surfaces in the noun bench as voiced (-/z/), unvoiced (-/s/) or syllabic (-/əz/). Our results have implications for understanding how morphological elements are encoded in the lexicon and the nature of morpho-phonological mechanisms involved in speech production.
The two-stage theory of lexical production distinguishes the retrieval of lemmas from the subsequent retrieval of the forms of words. The information made available by lemma retrieval includes semantic and grammatical details that are specific to a particular word, but not the direct specification of its phonological or orthographic form. This theory makes very strong predictions regarding the dissociability of these information types. In this report we present the case of an Italian anomic patient whose performance bears on these predictions. In various naming tasks this patient's intact ability to identify the grammatical gender of words that he cannot produce stands in stark contrast with his inability to provide any information regarding particular lexical forms. We document the reliability of this performance pattern, and we discuss the significance of this pattern both in terms of the support it provides for the two-stage theory of lexical retrieval and in terms of the evidence it furnishes regarding the mental specification of grammatical information.
A. Caramazza, A. Costa, M. Miozzo, and Y. Bi (2001) reported a series of experiments showing that naming latencies for homophones are determined by specific-word frequency (e.g., frequency of nun) and not homophone frequency (frequency of nun none). J. D. Jescheniak, A. S. Meyer, and W. J. M. Levelt (2003) have challenged these studies on a variety of grounds. Here we argue that these criticisms are not well founded and try to clarify the theoretical issues that can be meaningfully addressed by considering the effects of frequency on homophone production. We conclude that the evidence from homophone production cannot be considered to provide support to 2-layer theories of the lexical system.
Abstract We report on two brain-damaged patients who show contrasting patterns of deficits in memory and language functioning. One patient (AW) suffers from a lexical retrieval deficit and failed to produce many irregularly inflected words such as spun, forgotten, andmice, but demonstrated intact production of regularly inflected words such aswalked andrats. She also had preserved declarative memory for facts and events. The other patient (VP) presented with a severe declarative memory deficit but showed no signs of impairment in producing either regular or irregular inflections. These patterns of deficits reveal that the retrieval of irregular inflections proceeds relatively autonomously with respect to declarative memory. We interpret these deficits with reference to three current theories of lexical structure: (a) Pinker's “words and rules” account, which assumes distinct mechanisms for processing regular and irregular inflections and proposes that lexical and semantic processing are subserved by distinct but interacting cognitive systems; (b) Ullman's “declarative/procedural” model, which assumes that mechanisms for the retrieval of irregular inflections are part of declarative memory; (c) Joanisse and Seidenberg's connectionist model, in which semantic information is critical for the retrieval of irregular inflections.
Parkin and Stewart (this issue) criticize Sartori, Miozzo, and Job's (this issue) demonstration of a category-specific naming impairment for living things when sets of living and non-living things were matched for familiarity, visual complexity, name frequency, and visual similarity. In this paper we discuss the points raised by Parkin and Stewart and argue that they do not undermine our demonstration of a category-specific impairment.
