Content-function word production in Mandarin-speaking Broca's aphasia: a generative approach.

Introduction: Broca's aphasia is a non-fluent language disorder typically associated with reduced grammatical encoding and relatively preserved lexical meaning. While content-function asymmetries have been extensively documented for Indo-European languages, corresponding evidence from Mandarin remains limited, despite Mandarin's typological profile as an isolating, topic-prominent language whose grammatical relations are largely expressed through word order and functional particles rather than inflections. Methods: We analyzed picture-description discourse (Western Aphasia Battery picnic scene) from 18 Mandarin-speaking individuals with Broca's aphasia and 18 healthy controls. Transcripts were segmented at the morpheme level and coded into lexical versus functional categories and their subtypes under a generative architecture. Results: Relative to the healthy controls, the patients showed a markedly pronounced content-function imbalance, producing much higher proportions of content morphemes than function morphemes in connected speech. The patients produced substantially more content items than function ones; within lexical categories, nouns constituted the largest lexical category, whereas verb proportions did not differ significantly between groups in the present sample. Within the functional domain, elements plausibly associated with lower nominal structure (e.g., demonstratives and classifiers) were sporadically available, while categories linked to higher clausal and discourse-related structure (e.g., complementizer- and topic-related markers) were near-absent. Discussion: Overall, the results indicate a robust content function imbalance in Mandarin Broca's aphasia and motivate further individual-level work on which functional categories are most vulnerable, with potential implications for assessment and rehabilitation targets.