Young children's use of prosody in sentence parsing

Korean children's ability to use prosodic phrasing in sentence comprehension was studied using two types of ambiguity. First, we examined a word-segmentation ambiguity in which placement of the phrasal boundary leads to different interpretations of a sentence. Next, we examined a syntactic ambiguity in which the same words were differently grouped into syntactic phrases by prosodic demarcation. Children aged 3 or 4 years showed that they could use prosodic information to segment utterances and to derive the meaning of ambiguous sentences when the sentences only contained a word-segmentation ambiguity. However, even 5- to 6-year-old children were not able to reliably resolve the second type of ambiguity, an ambiguity of phrasal grouping, by using prosodic information. The results demonstrate that children's difficulties in dealing with structural ambiguity are not due to their inability to use prosodic information.     

Assignment of thematic roles to nouns in sentence comprehension by an agrammatic patient

We present the results of a study of sentence comprehension in an agrammatic patient. The patient showed striking regularities in interpreting a wide variety of sentence structures. We analyze her performance as the result of attempting to interpret a simplified syntactic structure, consisting of a linear sequence of lexical categories, according to a number of simple interpretive strategies.     

Automatic syntactic computation and use of semantic information during sentence comprehension

Summary The paper represents a contribution to the issue of the differential effects of syntactic, semantic and pragmatic information in the process of sentence comprehension. The results of four experiments are reported, in which sentences containing syntactic, semantic and pragmatic violations were presented with different tasks to see how these violations affected language comprehension, how easily they were detected and whether they affected sentence comprehension even when they were not explicitly recognized. The main results can be summarized as follows. First, the most relevant cues used to comprehend a sentence are not so much syntactic, but semantic or pragmatic. Second, with difficult or anomalous linguistic input, syntactic cues become more important. Third, even when the reader is not aware of syntactic violations, these seem to affect his processing of the linguistic input. This suggests the hypothesis of an automatic computation of syntactic information, the output of which is, however, used only when evidence coming from other sources, semantic or pragmatic, is insufficient or not clear enough.     

Syntactic loss versus processing deficit: an assessment of two theories of agrammatism and syntactic comprehension deficits

This research evaluated Grodzinsky's (1984, 1986a) syntactic loss and Kolk and van Grunsven's (1985) working memory impairment explanations of syntactic comprehension deficits in agrammatic aphasics. Four aphasic patients were evaluated who showed different patterns of impairment on morphological and structural aspects of production. The comprehension tasks compared performance on full and truncated passive sentences. The syntactic loss hypothesis predicted worse performance on truncated than full passives, while the working memory deficit hypothesis predicted the reverse. Neither hypothesis was supported, as the patients performed at a similar level on both types of passives. In addition, there was little relation between the patients' production indices and their comprehension level. The results argue against any global theory of agrammatism that attempts to attribute all agrammatic speech and co-occurring syntactic comprehension deficits to the same source.     

Pronoun comprehension in aphasia: a comparison of three languages

The research reported here investigated the effect of phonological and syntactic factors on the processing of pronouns by aphasics. The comprehension of these "closed-class" elements was studied in three different languages: French, Dutch, and German. The cross-linguistic design made it possible to vary phonological status (clitic/nonclitic) and phrasal category (noun phrase/prepositional phrase) as well as grammatical relation (direct/indirect object) while keeping class membership (closed class) and meaning constant. A sentence-picture matching task was given to 20 German-speaking, 16 Dutch-speaking, and 14 French-speaking aphasics, half of each language group being classified as agrammatic Broca's and half as paragrammatic Wernicke's aphasics. The results suggest that Broca's aphasics' limitations in retrieving pronouns, and therefore other closed-class elements, are not a function of either phonological status, phrasal category, or grammatical relation. These subjects' observed high level of performance on pronouns in language comprehension appears due to the kind of semantic and syntactic information they encode. Our findings indicate that a more refined distinction than closed class vs. open class is necessary.     

Dissociations among functional categories in Korean agrammatism

This study investigated the hypothesis that the syntactic trees formed by individuals with agrammatic aphasia cannot be constructed any higher than an impaired node as suggested by the tree-pruning hypothesis (Friedman, 1994; Friedmann & Grodzinsky, 1997) and hypothesis. It also examined their following implication that the members of a certain functional category are subject to the same degree of impairment. Two experiments were conducted to investigate a Korean agrammatic patient's use and understanding of three functional categories--Mood, Tense, and Complementizer. The results showed a dissociation among functional categories that preserves the higher node while leaving the lower node impaired both in production and comprehension. Another dissociation was found among members of the same category depending on their linear position in the clause. These results contrast with the predictions of the tree-pruning hypothesis, suggesting that the nearer to the end of the clause a functional element is located, the better it is preserved in Korean agrammatism.     

Articulatory and phonological deficits in short-term memory and their relation to syntactic processing

The relationships between sentence comprehension deficits and deficits in the articulatory or phonological components of short-term memory were investigated. Nonfluent agrammatic patients showed very poor comprehension of syntax while a group of nonfluent patients who were not agrammatic showed good comprehension, despite both groups showing similar degrees of deficits in an articulatory component of memory. The results imply that a disruption of inner rehearsal has little consequence for auditory sentence comprehension, and that the syntactic comprehension deficits of the agrammatic patients could not be attributed to their memory deficit. A patient with a disruption in phonological storage showed good comprehension for many sentences, but was impaired when a difficult syntactic structure was encountered early in a sentence. It was proposed that phonological storage serves to hold words in a phonological form when sentence processing cannot keep pace with sentence input. Although a role for phonological storage was postulated, the impressive degree of syntactic processing that could be carried out by patients with very restricted memory spans implies that there is little overlap between the memory systems disrupted in these patients and the working memory system presumed to be involved in sentence comprehension.     

Closed-class immanence in sentence production

The closed-class hypothesis asserts that function words play a privileged role in syntactic processes. In language production, the claim is that such words are intrinsic to, identified with, or immanent in phrasal skeletons. Two experiments tested this hypothesis with a syntactic priming procedure. In both, subjects tended to produce utterances in the same syntactic forms as priming sentences, with the structures of the self-generated sentences varying as a function of differences in the structures of the primes. Changes in the closed-class elements of the priming sentences had no effect on this tendency over and above the impact of the structural changes. These results suggest that free-standing closed-class morphemes are not inherent components of the structural frames of English sentences.     

Does morphology make the difference? Agrammatic sentence comprehension in German

This study examines the syntactic comprehension of seven German agrammatic speakers. The German language allows the study of the interaction of syntactic principles and morphological devices in the comprehension process. In addition, due to its relatively free word order, German allows the study of strictly minimal pairs of canonical and non-canonical sentences in addition to the rather controversial active-passive contrast. A central research question was whether the pattern of agrammatic comprehension predicted by the trace deletion hypothesis (TDH, Grodzinsky, 1990, 1995), relatively normal comprehension performance of canonical sentences and chance performance on non-canonical sentences, can be found in a language with richer morphology than English. The generalisability of the TDH-pattern to morphologically rich languages is not obvious, given that case morphology in particular can provide explicit cues to the detection of the agent and patient roles in a sentence. The results of this study indicate that morphology does not make a difference. Furthermore, the group results are in line with the TDH-predictions only for number marked sentences but not for case marked sentences. However, single case analysis reveals different patterns of syntactic comprehension in agrammatic patients, a spectrum that encompasses near-normal comprehension of canonical and non-canonical sentences, overall chance performance, and TDH-like profiles.     

Real-time comprehension processes in agrammatism: A case study

The ability of an agrammatic patient to construct structural syntactic and interpretative representations on-line was tested in two experiments. The first focused on global representations spanning an entire utterance, while the second examined lexical syntactic and semantic constraints on verb-argument relations. An off-line version of the second experiment was also carried out. There were two major findings. First, the patient could construct a semantic, but not syntactic, representation of an utterance. Second, he was much more dependent than normal upon pragmatic information. These results are discussed with respect to current claims about the nature of agrammatic comprehension deficits.     

Comprehension of sentence structure in anomic and conduction aphasia

Picture-pointing auditory and reading comprehension tests were administered to anomic and conduction aphasics. Subjects responded to active sentences of the present progressive form. The possible errors which a subject could make on these experimental tasks included failure to correctly interpret noun order, number, or lexical meaning. Both groups made significantly more correct responses than error responses. Of their error responses, noun-order errors significantly exceeded number and lexical errors for which no differences were observed. When compared with results previously obtained for agrammatic Broca's aphasics, no differences in the pattern of errors were identified. These results are discussed relative to current theories of syntactic processing and for the mechanisms which account for these syntactic comprehension deficits following aphasia.     

Syntactic and semantic contributions to sentence comprehension in agrammatism

Five aphasic subjects, who demonstrated agrammatic speech, and eight control subjects were presented with a sentence-picture matching task in which the factors of syntactic complexity, semantic reversibility, and sentence plausibility were independently varied. A subset of the sentences was patterned after that presented by A. Caramazza and E. Zurif (1976, Brain and Language, 5, 572-583) who concluded that Broca's aphasics rely on semantic constraints instead of syntactic information for sentence comprehension. Our aphasic subjects showed the same pattern of performance on this subset of sentences. However, the results from the full set of sentence materials we tested show that the aphasic subjects could perform some sentence level syntactic analyses, even when syntactic information conflicted with semantic constraints. The aphasic subjects correctly interpreted most active and passive sentences. They failed, however, to assign thematic roles and adjectives in center-embedded relative sentences, and instead relied on nonsyntactic information. These results show that both semantic and syntactic information contributed to sentence comprehension in the aphasic subjects we tested, in contrast to previous claims that syntactic and semantic processes are completely dissociated in this population.     

Syntactic breakdown and recovery of clausal structure in agrammatism

We studied the recovery of clause structures in four agrammatic patients by performing a longitudinal analysis of their spontaneous production. We classified their utterances in terms of legitimacy of the syntactic structure and rate of subordination. The results show that, initially, patients omit verbs, avoid subordination, just employ present tense, and substitute finite verbs with infinitives. During the recovery they start employing other tenses and subordinate clauses and reduce the use of infinitives. Data suggest a mixed syntactic and morphological origin of the impairment. Assuming that phrasal representations are built bottom-up from an array of lexical items, we propose that syntactic structures recover stepwise, with the lower portion of the syntactic tree becoming accessible before higher portions. We claim that, despite superficial similarities between agrammatic and children's speech, e.g., use of infinitives instead of finite verbs, a unified account is not viable.     

Working memory and planning during sentence production

Speakers retrieve conceptual, syntactic and lexical information in advance of articulation during sentence production. What type of working memory (WM) store is used to hold the planned information before speaking? To address this question, we measured onset latencies when subjects produced sentences that began with either a complex or a simple initial noun phrase, while holding semantic, phonological or spatial information in WM. Although we found that subjects had longer onset latencies for sentences beginning with a complex noun phrase, showing a phrasal scope of planning, the magnitude of this complexity effect was not affected by any type of WM load. However, subjects made more syntactic errors (but not lexical errors) for sentences beginning with a complex noun phrase, suggesting that advance planning for these phrases occurs at a syntactic rather than lexical–semantic level, which may account for the lack of effect with various types of WM load in the current study.     

Sensitivity to grammatical structure in so-called agrammatic aphasics

Comprehension failures in agrammatic aphasics, as well as their difficulties in sentence construction, have been attributed to an underlying deficit involving the retrieval of syntactic structure. In this study we show that four agrammatic patients display a remarkable sensitivity to structural information, as indicated by their performance on a grammaticality judgment task. These results indicate significant sparing of syntactic knowledge in agrammatism, and suggest that the sentence comprehension disturbances in these patients do not reflect loss of the capacity to recover syntactic structure. In particular, accounts of the comprehension deficit in agrammatism that implicate a failure to exploit information carried by the closed class (function word) vocabulary are called seriously into question. Alternative explanations of the comprehension problem in agrammatism are explored.     

Verb processing during sentence comprehension in aphasia

This study examines verb processing during on-line sentence comprehension in aphasia. We describe two experiments that explore whether a group of Broca's aphasics, who were agrammatic in comprehension as well as speech, a group of fluent aphasics, and a group of normal controls are sensitive to the argument structure arrangements of verbs. Subjects had to perform a complex secondary task both in the immediate vicinity of the verb and also at a point well past the verb while listening to sentences for meaning. Reaction times to this secondary task show that both normal controls and agrammatic Broca's aphasic subjects activate multiple argument structure possibilities for a verb in the vicinity of the verb, yet at a point downstream from the verb such effects disappear. These data suggest that the problems agrammatic subjects show with verbs in sentence comprehension, and the general lexical access deficit also recently claimed to be part of the agrammatics' problem, may not extend to the real-time processing of verbs and their arguments. Fluent aphasic subjects, on the other hand, do not show sensitivity to the argument structure properties of verbs, suggesting that these patients may have a semantic-like sentence processing deficit.     

Comprehension of sentences with stylistic inversion by French aphasic patients

Three French-speaking agrammatic aphasics and three French-speaking Conduction aphasics were tested for comprehension of Active, Passive, Cleft-Subject, Cleft-Object, and Cleft-Object sentences with Stylistic Inversion using an object manipulation test. The agrammatic patients consistently reversed thematic roles in the latter sentence type, and the Conduction aphasics performed at chance. The results are discussed in relationship to existing models of aphasic impairments in assigning syntactic structures and using them to determine thematic roles in sentences. We conclude that the results for the agrammatic patients demonstrate the importance of compensatory mechanisms underlying aphasic comprehension and the results in the Conduction aphasics indicate the importance of working memory deficits in determining such deficits. The results are also relevant to models of normal syntactic structure.     

Agrammatic aphasic subjects' comprehension of subject and object extracted Wh questions

This study attempted to replicate the unusual wh question comprehension pattern of Hickok and Avrutin's (1996) subjects who showed an expected subject/object extraction asymmetry for which NP questions, but not for who questions. We also examined comprehension of what and which one questions, which are similar to who and which NP questions, respectively, and we examined passivized wh questions in order to test predictions of Grodzinsky's (1995) restrictive theory of trace deletion, the Trace-Based Account (TBA). Results, using both a figurine manipulation task and a picture pointing task, showed that only one of four agrammatic (Broca's) aphasic subjects showed the pattern reported by Hickok and Avrutin and that this pattern extended to comprehension of what and which one questions. One of the subjects showed subject/object asymmetry for all wh questions tested, as would be predicted by the original trace deletion hypothesis (Grodzinsky, 1984), and two subjects showed neither pattern. None of our subjects demonstrated ability to comprehend passivized wh questions as predicted by the TBA. We discuss our findings in terms of the lack of homogeneity of wh question comprehension among individuals with agrammatic aphasia and we explore alternatives to the syntactic explanation for differences between who and which NP question comprehension advanced by Hickok and Avrutin.     

Syntactic comprehension deficits in agrammatism

Eleven agrammatic and 16 fluent aphasic patients were given a comprehension task consisting of simple, active and passive reversible sentences. The purpose of the study is to reconsider the comprehension disorders in agrammatism, and particularly of passive reversible sentences, to test to what extent Grodzinsky's trace deletion hypothesis (TDH) is generalizable to other types of NP-movement, and finally to ascertain whether the pattern of impairment observed in agrammatism differs from that of fluent aphasic patients. The study confirms that trace analysis may be selectively impaired in agrammatism. However, this deficit is not the only mechanism underlying comprehension disorders and cannot be said to occur in all agrammatic patients. Comprehension disorders also involve the processing of clitic object pronouns which also underly NP-movement. Finally, the impairment found in fluent aphasic patients differs, both in type and severity, from that of agrammatic patients, thus confirming the peculiar aspects of the agrammatic comprehension deficit suggested by Grodzinsky's TDH.     

Syntactic priming and the lexical boost effect during sentence production and sentence comprehension: An fMRI study

Behavioral syntactic priming effects during sentence comprehension are typically observed only if both the syntactic structure and lexical head are repeated. In contrast, during production syntactic priming occurs with structure repetition alone, but the effect is boosted by repetition of the lexical head. We used fMRI to investigate the neuronal correlates of syntactic priming and lexical boost effects during sentence production and comprehension. The critical measure was the magnitude of fMRI adaptation to repetition of sentences in active or passive voice, with or without verb repetition. In conditions with repeated verbs, we observed adaptation to structure repetition in the left IFG and MTG, for active and passive voice. However, in the absence of repeated verbs, adaptation occurred only for passive sentences. None of the fMRI adaptation effects yielded differential effects for production versus comprehension, suggesting that sentence comprehension and production are subserved by the same neuronal infrastructure for syntactic processing.