The Production of Clitics in Serbian Speakers with Stroke Aphasia

Background/Objectives: Cross-linguistic studies show that the production of morphosyntactic elements (e.g., clitics) is problematic and often omitted in nonfluent agrammatic aphasia (NFA), with the degree of impairment varying across languages. Serbian, with its rich clitic system, provides a sensitive window into grammatical impairment. This study is the first to examine the production of proclitics and enclitics in Serbian speakers with aphasia and their relationship to short-term and working memory. Methods: Forty-six individuals with stroke-induced aphasia (25 NFA and 21 fluent aphasia [FA]) and 54 healthy controls completed an experimental Serbian clitic production test. Participants were prompted to produce clitic sentences (12 proclitics, such as prepositions or conjunctions, and 18 clitics, such as pronouns or auxiliary verbs) in response to various scenarios. Performances were correlated with sentence repetition and digit span (forward/backward). Results: Both aphasia groups produced significantly fewer clitics than controls (p < 0.001). Participants with NFA produced fewer overall clitics and showed no clitic type effects (p = 0.329), whereas participants with FA produced proclitics more accurately than enclitics (p = 0.028). Clitic production correlated with performance on sentence repetition and digit span tasks, but patterns differed by aphasia group. In NFA, both enclitics and proclitics were associated with sentence repetition and digit span (p < 0.05), whereas in FA, these measures were primarily associated with enclitic production (p < 0.05). Conclusions: Clitics production distinguishes nonfluent from fluent aphasia in Serbian and is differentially supported by working and verbal memory resources. The Serbian clitic production test reveals a selective proclitic advantage that is observed only in fluent aphasia, serving as a sensitive clinical marker in this population.