Oscar Swan's Polish grammar (Univ. of Pittsburgh)
A full academic Polish grammar in English, free as a PDF from Pittsburgh.
BooksWebsitesFreeIntermediateAdvancedA2–C1
What it actually is
Oscar Swan's grammar of contemporary Polish, hosted free by the University of Pittsburgh alongside his first-year Polish lesson materials, is the most thorough English-language treatment of Polish grammar you can get without paying. It is the reference to consult when a learner site's explanation of aspect or motion verbs leaves you unconvinced. The site itself has not been touched in about two decades and looks it — go straight to the PDF.
What it covers
- Grammar
- Reading
- Writing