This is a thing that I have been thinking about for a while. I know that PIE did not have gender distinction in verb forms, and its presence in modern Slavic languages must be an innovation.
If I am correct this phenomenon occurs exclusively in the Slavic family (I still have in mind only IE languages). My questions are:
- What is the probable origin of it, how did it develop within the Slavic group ?
- Do any IE families or languages besides Slavic contrast between masculine and feminine verbs forms, even in the slightest degree ?
- Are there any universal lingustic processes that may lead to that ?
I want to emphasize that I am only concerned about the verb.
Of course any references to articles, books etc. will be very welcome.