In Kerala we have different dialects, but I would also consider Malayalam itself as a Tamil dialect!

The use of "da" and "ra" is part of the Malayalam language, but you only use it for your friends, and colleagues, not for elders and respectable people. For example, if I was tellin my younger brother to take something, I would say "edraa!", or if I tell him to let go, "vidraa!". Or if I tell him to come, I would say "vaada", and if I tell him to go "podaa!".