Voicing and gemination in japanese consonants
I've found that there is a japanese morphophonology phenomenon called"Rendaku", and I can undestand this when it occurs to repetitive words like ひとびと or ときどき, but why ひらがな if かたかな doesn't change?
Is there a specific rule that could explain it more clearly this phenomenon? Is rendaku just one of various kinds of voicing modification, could you tell me other kind of changing pronunciation?