Agrammatism is a frequent sequela of Broca's aphasia that manifests itself in omission and/or substitution of the grammatical morphemes in spontaneous and constrained speech. The hierarchical structure of syntactic trees has been proposed as an account for difficulty across grammatical morphemes (e.g., tense, agreement, and negation). Supporting data have come from different languages including Arabic. Other studies have produced different results with different accounts for the clausal functional category errors. Moreover, these studies have not produced evidence of whether the tense agreement dissociation is a sentence production phenomenon or if it may include other modalities. This study investigated question production as well as production and comprehension of grammatical morphemes corresponding to tense, agreement, and negation in Arabic-Jordanian speakers with agrammatism. Additionally, it investigated whether production of functional category in Arabic Jordanian agrammatism reflects the hierarchical structure proposed by the tree pruning hypothesis (TPH). Control data was obtained from fifteen non-brain damaged Arabic Jordanian speakers. This control data demonstrated that the selected stimuli met testing criteria. The experimental group included fifteen patients diagnosed with Broca's aphasia and agrammatism. There were six females and nine males in each group. Their age ranged from 40 to 80 years. Their level of education ranged from zero to fourteen years. The data of this study was composed of different experiments that had separate scoring and data analysis procedures specified for each experimental task. Two expressive tasks (sentence elicitation and repetition) were used to examine production of Wh and yes/no questions (Experiment 1). Grammatical morphemes corresponding to tense, agreement, and negation were examined through a sentence completion task (Experiments 2), and comprehension of tense and agreement through grammaticality judgments (Experiment 3). Results of this study indicated near ceiling performance of control subjects on question production, question repetition, tense, agreement, and negation production, as well as grammaticality judgment tasks. In contrast, individuals with agrammatism demonstrated deficits across each of these tasks. Production of yes/no questions was much better preserved than Wh-questions. However, there was no statistical difference between the production of argument Wh-questions and adjunct Wh-questions. The results of the question repetition task for the agrammatic group revealed that the production of matrix questions repetition was better than that of embedded questions repetition. Sentence completion task results revealed dissociation among functional categories; that is, tense, agreement, and negation were not equally impaired in patients' production. The production of agreement inflections and negation production was much better than that of tense inflections. The results of the grammaticality judgment task revealed that participants with agrammatism had more errors than the control group. However, there was no significant difference in participants' sensitivity between tense and agreement violations. A thorough analysis of each one of these findings was discussed to conclude that TPH is an adequate explanation of the data. TPH states that the syntactic tree is pruned from the tense node and up, leaving the lower nodes such as agreement and negation nodes with less impairment. The resulting data thus provides a good addition to the controversy about the universal and language specific characteristics of agrammatism. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]