Production of time reference in Turkish Broca’s aphasia: The effect of morphological complexity

ABSTRACT

In PWA (people with aphasia) difficulties with sentences that refer to the past compared to non-past time reference have been shown for many languages, including Turkish. However, the impact of morphological complexity on past time reference ability in production has not yet been reported for Turkish-speaking PWA. Turkish, where verb forms have complex inflectional paradigms and exhibit overt and non-overt morphology, facilitates the examination of the effects of morphological complexity. The current study has two objectives: 1) to investigate whether the morphological complexity of the verb form affects time reference production of Turkish-speaking PWA and 2) to provide analysis for the error patterns discovered. Seventeen Turkish individuals with Broca’s aphasia who were matched in age with a control group of 17 neurologically intact Turkish individuals were tested with a picture sentence completion task. Test conditions were present progressive, simple past, past perfect, past progressive, and future tense. The task required the participants to complete each sentence frame with a verb. Our findings show that Turkish-speaking PWA were more successful in producing verb forms referring to non-past than verb forms referring to the past time reference. The current study supports previous findings that past is more difficult than non-past time reference for Turkish-speaking PWA. In terms of morphological complexity, we find that PWA were more impaired when producing morphologically complex verb forms rather than morphologically simple forms. We argue that these impairments lie in the realization of overt morphology.

KEYWORDS:

• Time reference
• Broca’s aphasia
• Turkish
• morphological complexity
• verb inflection

Acknowledgments

The authors thank Kelly Swenson and Prof. Susan Curtiss for proofreading the manuscript, as well as all the participants staff at the rehabilitation centers/clinics for being part of this study.

Disclosure Statement

No potential competing interest was reported by the authors.

Supplemental Material

Supplemental data for this article can be accessed on the publisher’s website.

Notes

¹ Although the adverbs daha önce ‘previously’ and biraz önce ‘short before’ can be used with all past verb forms in our stimuli, the frequency of the collocation correspondences between these adverbs and the verb forms are significantly different. The data provided by the TS Corpus Project (Sezer, 2017) reveal that the collocation correspondences between daha önce ‘previously’ and the verb forms V+mIş+tI and V+(I)yor+du is greater than the collocation correspondences between biraz önce ‘short before’ and those verb forms (76% and 23%, respectively). However, the collocation correspondences between daha önce ‘previously’ and the verb form V+DI is quite similar to the collocation correspondences between biraz önce ‘short before’ and V+DI form (46% and 54%, respectively).

Additional information

Funding

This work was supported by the Ankara University Scientific Research Projects Coordinatorship (BAP) [14L0649001].