Disentangling Time Reference and Morphological Complexity in Tagalog Agrammatism

This study investigates time reference expressed through verb inflections in Tagalog-speaking individuals with agrammatism. The "Past Discourse-Linking Hypothesis" (PADILIH) suggests that past time reference is particularly challenging for agrammatic speakers due to its need for discourse-linking, rather than its morphological complexity. Tagalog, an agglutinative language, exhibits varying and non-equal morphological complexity across time references, with past forms being morphologically simpler than present and future forms. Using the Tagalog adaptation of the "Test Assessing Reference of Time" (TART), this study tested ten agrammatic aphasia and ten non-brain damaged participants on verb production and comprehension. The aphasia group performed significantly poorer than the control group across all time references. Within the aphasia group, comprehension was highest in the present condition, followed by the past, and lowest in the future. In contrast, production was highest in the past condition, while both future and present conditions equally yielded the lowest scores. These findings revealed statistically significant group and time reference effects, suggesting that morphological complexity influences how individuals with agrammatism compensate for verb inflection deficits. These findings offer insights that may challenge existing theories of agrammatism and contribute to a more refined understanding of verb morphology and time reference realization.