Is there a relation between working memory limitation and sentence comprehension? A study of conduction and agrammatic aphasia

The study explored the nature of the relation between phonological working memory and sentence comprehension in conduction and agrammatic aphasia. We compared two types of processing required during sentence comprehension: syntactic-semantic and word-form(phonological) reactivation, in 12 individuals with input-buffer conduction-aphasia(repetition), 3 with output-buffer conduction aphasia(reproduction) and 7 with agrammatism. This was done via the analysis of comprehension of relative-clauses, sentence with lexical ambiguity, and rhyming judgment. The results of the 3 experiments indicated that phonological working memory limitation only hampers comprehension when phonological reactivation is required, and the distance between the initial word and its reactivation exceeds the WM limitation

Speech production in Broca’s agrammatic aphasia: Syntactic tree pruning

Broca’s agrammatic aphasia entails a syntactic deficit both in sentence comprehension and in sentence production. This chapter describes the intriguing pattern of deficits in speech production, and shows that this type of inquiry interacts with linguistic theory as well as with knowledge about brain-language relations. The syntactic tree, a syntactic construct that has originally been suggested based on purely linguistic grounds, is shown to be a useful tool to describe the deficit in production in agrammatism, and the role of the impaired brain area in syntactic production. The general idea is that the selective pattern of impairment in Broca’s agrammatic aphasia and the dissociations witnessed within and between languages follow from the inaccessibility of high nodes of the syntactic tree to agrammatic speakers. This causes syntactic structures that relate to high nodes of the tree to be impaired in agrammatism, whereas lower structures are unimpaired. The relative order of various syntactic abilities on the tree can also serve to explain degrees of agrammatic severity, as well as the path of spontaneous recovery from agrammatism

Question production in agrammatism: The Tree Pruning Hypothesis

This study investigated question production in agrammatic aphasia, focusing on the comparison between Wh questions and yes/no questions and on the interaction between the question production deficit and language-specific properties. A total of 16 agrammatic aphasics (13 Hebrew speakers, 2 Palestinian Arabic speakers, and 1 English speaker) participated in the study, which included sentence elicitation and repetition tasks. In addition, the patients ’ spontaneous speech, containing 2272 utterances, was analyzed. The main findings were that Hebrewand Arabic-speaking agrammatics encounter severe difficulties in Wh question production but retain the ability to produce yes/no questions. English-speaking agrammatics do not show this dissociation and can form neither Wh nor yes/no questions. These dissociations as well as the error pattern, are explained by reference to the Tree Pruning Hypothesis, according to which the highest nodes of the syntactic tree, which are required for Wh questions in Hebrew, Arabic, and English and for yes/no questions in English, are impaired or inaccessible in agrammatism

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relative clauses with resumptive pronoun

In Language Acquisition, 14(4), 2007. Young Children and A-chains: The Acquisition of Hebrew Unaccusatives

SV sentences with unaccusative verbs like The leaf fell involve movement from object to subject position. This line of studies tested whether young children can produce this movement and whether they represent SV sentences with unaccusatives as derived by movement. In Hebrew, unaccusatives appear in both SV and VS orders. This optionality allows for the testing of the acquisition of object-to-subject movement. If it is not yet acquired, children are expected to produce unaccusatives in their base-generated VS order, and refrain from the SV order, or, if they assign unaccusatives an analysis of unergatives, they are expected to produce unaccusatives only in SV order, as they do with unergatives, and without possessive datives. Seven experiments assessed the production of unaccusatives and unergatives in 136 1;9-4;0 year-old Hebrew-speakers, using tasks of sentence repetition, story retelling, and analysis of spontaneous speech. The results indicated that children younger than 2 years already produce SV sentences with unaccusatives. They distinguish between unaccusatives and unergatives, as they use both VS and SV orders for unaccusatives, but only SV for unergatives. They use possessive datives with unaccusatives, indicating that they analyze the argument of the unaccusative as an internal argument. Thus, children younger than two years can already move the argument of unaccusatives from object to subject position, namely, they can construct Achains. 1