Interpretable vs. uninterpretable features: Evidence from six Greek-speaking agrammatic patients

The aim of the present study is to examine the validity of the tree-pruning hypothesis (TPH) put forward by [Friedmann, N., & Grodzinsky, Y. (1997). Tense and agreement in agrammatic production: Pruning the syntactic tree. Brain and Language, 56, 397-425]. The TPH accounts for the deficits agrammatic Broca's aphasic have in relation to verb inflections in syntactic terms and postulates that such patients cannot construct syntactic trees higher than an impaired node, the pruning site, while nodes located lower remain intact. This paper reports the performance of six Greek-speaking agrammatic patients. The experiments investigated the patients' ability to produce tense, agreement and aspect in single word and sentential tasks and their ability to judge the grammaticality of the same inflectional markers within sentences. In single word tasks the patients were impaired in all inflectional markers to a similar degree, while in sentential tasks, both in production and in grammaticality judgment, aspect and tense were more impaired than agreement. The results are similar to those in [Friedmann, N., & Grodzinsky, Y. (1997). Tense and agreement in agrammatic production: pruning the syntactic tree. Brain and Language, 56, 397-425]. However, in the syntactic clause in Greek, agreement is thought to be located higher than tense and aspect, and aspect is located lower than tense. These results, therefore, do not support predictions of the TPH insofar as tense and aspect that are lower in the syntactic tree were found to be more impaired than agreement. Instead, the results are interpreted within recent formulations of minimalism that distinguish between interpretable (tense and aspect) and uninterpretable (agreement) features and the morphophonological evaluation operations associated with them. (c) 2005 Elsevier Ltd. All rights reserved.