Comprehension of word order in Turkish aphasia

ABSTRACT

Background

People with aphasia (PWA) have been shown to encounter difficulties in processing sentences with non-canonical (i.e., derived) word order. Although previous research points to similar impairment patterns in non-canonical structures in aphasia across many languages, there is only little agreement among authors why PWA experience these impairments.

Aims

This study aims to unveil whether and how far fluent and non-fluent PWA speaking Turkish, a flexible word order language, are impaired in comprehending different conditions of word order alignments in declarative sentences.

Methods & Procedures

Using a picture-matching paradigm, we examined two groups of Turkish speakers with aphasia: fluent PWA (n = 7) and non-fluent PWA (n = 10), and a matched reference group of non-brain-damaged controls (NBDs, n = 16). Participants listened to simple declarative sentences in four conditions: Subject – Object – Verb (SOV), SVO, OVS, and OSV. They were asked to point to the corresponding visual display that best depicts the sentence. Data were analysed with generalized linear mixed-effects regression models in R.

Outcomes & Results

Our findings have shown that the PWA performed less well than the NBDs overall, and that while the fluent PWA showed no condition differences at all, the non-fluent PWA performed worse in object-first (OVS/OSV) sentences than subject-first sentences (SOV/SVO), and no further condition differences were found.

Conclusions

We discuss that the data presented in this study support the theories that (i) predict derived structures to be affected in aphasia and that (ii) hold lexically restricted sentence material between moved objects and their base-generated positions to pose challenges in aphasic sentence comprehension. We also suggest that high structural frequency of subject-first sentences might have worked in favour of the PWA, rendering the comprehension of these structures easier to process.

KEYWORDS:

• Word order
• fluent aphasia
• non-fluent aphasia
• Turkish
• sentence comprehension

Acknowledgments

Dr Seçkin Arslan was supported by an Initiative of Excellence (IDEX) young researcher award granted by the French Government through the National Research Agency (ANR), and the University of Cote d’Azur, under reference no: ANR-15-IDEX-01. We would like to thank to all of our participants and their families for their patience during data collection, and to the three anonymous Aphasiology reviewers for their constructive feedback and comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. See also the Double Dependency Hypothesis (DDH; Mauner, Fromkin, & Cornell, 1993), another representational account, which holds that syntactic referential dependencies are impaired in aphasia, and hence, PWA are unable to process co-indexed dependencies.

2. VOS and VSO orders are out of the scope of this current study as they involve multiple rightward scrambling in Turkish, which makes all the post-verbal constituents non-hierarchically constructed (Kornfilt, 2005), and the theoretical approaches under investigation here do not make significant predictions about VSO and VOS. Furthermore, these word orders are extremely infrequent in Turkish.

Additional information

Funding

This work was supported by the Agence Nationale de la Recherche [ANR-15-IDEX-01].