Verbs: some properties and their consequences for agrammatic Broca's aphasia

It has repeatedly been shown that agrammatic Broca's aphasics have serious problems with the retrieval of verbs on action naming tests (Miceli, Silveri, Villa & Caramazza, 1984; Kohn, Lorch & Pearson, 1989; Basso, Razzano, Faglioni & Zanobio, 1990; Jonkers, 1998; Kim & Thompson, 2000). Less attention has been paid to the production of verbs at the sentence level (but see Miceli, Mazzuchi, Menn & Goodglass, 1983; Thompson, Shapiro, Li & Schendel, 1995; Thompson, Lange, Schneider & Shapiro, 1997; Bastiaanse & Van Zonneveld, 1998; Bastiaanse, Rispens & Van Zonneveld, 2000; Friedmann, 2000), although it has been mentioned that in agrammatic spontaneous speech verbs are lacking (Saffran, Berndt & Schwartz, 1989; Thompson et al., 1995, but see Bastiaanse & Jonkers, 1998).In this paper, three cross-linguistic studies are discussed to show that these problems with verbs have consequences for other grammatical morphemes and structures that have been mentioned to be impaired in agrammatic speech and that these consequences are different per language, depending on linguistic characteristics. The first study focuses on finiteness and compares the production of finite verbs in matrix and embedded clauses in Dutch and English, showing that a linguistic rule in Dutch (Verb Second), which does not exist in English, can explain the different performance of Dutch and English agrammatic Broca's aphasics. The second study focuses on determiners and (finite) verbs in German and shows that poor determiner production is directly related to poor verb production. The last study demonstrates that the ability to construct negative sentences is dependent on the language specific relation between verb movement and negation: Dutch and Norwegian agrammatics perform equally well on affirmative and negative sentences, whereas English and Spanish agrammatics are more impaired on negative sentences.Overall, these studies show that the problems agrammatics encounter with verbs and their properties have a spin-off on the production of other word-classes and that the characterization 'problems with grammatical morphemes' is too general for telegraphic speech.