"Is he cleaning with soap?"
Translation:Anasafisha na sabuni?
What's the difference between -osha, -safisha and -fua? Is it connected to what you are washing/cleaning or to the method being used?
Yes! :) 1) -osha (applicative from -oga) to wash (children for example; also "Umeosha vyombo?" - Have you done the dishes? as a set phrase) 2) -safisha (from safi) to clean (rooms) 3) -fua (actually from beating, also used for iron...) nguo - that is the only context in which it means "to wash" (due to the original way of doing your laundry with beating techniques)