Objectives: This study investigated the effects of healthy aging on sentence production in narrative discourse and examined the role of cognitive abilities and Lifelong Learning (LLL) in mitigating age-related decline. Methods: Three hundred and seven Italian-speaking adults (26–89 years) completed a narrative task elicited from five picture stimuli, alongside assessments of verbal working memory, sustained attention, and inhibitory control. Morphological and morphosyntactic measures (morphological errors and omissions of content and function words) and syntactic variables (complete sentences, subordinate clauses, and passive sentences) were analyzed. Results: Aging was associated with increased morphological and morphosyntactic errors and reduced syntactic complexity. These effects were non-linear for the % of morphological errors, the % of omission of content words, and the % of complete sentences and were more pronounced after age 70. LLL was negatively associated with morphological and morphosyntactic errors and positively associated with sentence production. Verbal working memory and sustained attention explained additional variance only for omissions of function words, whereas the passive component of verbal working memory only explained additional variance for complete sentence production. Conclusions: These findings suggest that aging affects both simple and complex sentence production, with declines related to morphological errors and omissions. LLL appears to buffer against some grammatical declines, suggesting a role for educational engagement in maintaining syntactic abilities. Clinically, assessing complex sentence production and considering LLL may improve diagnosis and intervention for language disorders in older adults.
