I don't know if there is any doubt that there is a translated EarthBound (Mother) prototype,.. and I don't know if this little piece has been brough to the public's eye.. but I was looking through an old Nintendo Power (Issue 21, February 1991), and I came across this GPC profile...
So it must mean that the GPCs were given translated prototypes.. I doubt this guy understands Japanese. And he didn't call it "Mother", he called it Earth Bound.
If this has already been shown, just delete it quickly to spare me the embarassment.