Specialized interrogative-based relative pronouns in Slavic languages

Relative clauses in some Slavic languages can be introduced by relative pronouns derived from interrogatives with specialized markers, such as ‑to in Bulgarian, ‑r in Slovenian, and što in Macedonian. The distribution of these pronouns varies drastically from language to language. While in Modern Standard Bulgarian, Slovenian, and Sorbian languages derived interrogative-based relative pronouns are used predominantly, Czech and Polish almost exclusively make use of relativizers which are not differentiated from interrogative pronouns, whereas Macedonian allows both types of relativizers in most contexts. Even though Macedonian is unique in this respect among modern standard varieties, the competition between specialized and non-specialized relative pronouns is more widespread among a few non-standard and older Slavic varieties. Despite the fact that specialized relative pronouns are prevalent in some varieties and exceedingly rare in others, the patterns of their distribution show some striking similarities across Slavic languages. The use of specialized relative pronouns abides by the semantic hierarchy by Alexander Grosu and Fred Landman, relative marking being most prevalent in appositive relative clauses and least common in maximalizing contexts.