The International Classification of Function, Health and Disability (ICF) underscores a functional approach to aphasia assessment and therapy. The widespread uptake of the ICF necessitates a reflection whether the existing knowledge base on the Polish language of aphasia will permit speech-language pathologists in Poland to make a strong contribution to this international trend. Using the PRISMA-ScR methodology, a scoping review was conducted to describe and summarise the current state of research on the impact of aphasia on the subsystems of the Polish language and its mental processing. The findings indicate that although empirical studies of the Polish language of aphasia have so far addressed all the language subsystems, the level of scientific evidence in this area is low and the resulting knowledge base is incomplete and fragmented. There are significant research gaps, particularly in regard to pragmatics and discourse in aphasia, which need to be filled, so that the new empirical evidence can be used to develop functionally oriented and consequence-based clinical tools and methods.