… he doesn’t speak Castilian Spanish with an accent… Castilian Spanish is a Spanish dialect, which the Pope doesn’t speak. He speaks Argentinian Spanish. If you’re trying to use “Castilian Spanish” to mean “Spanish” then for Lope’s sake I beg you, just pick one of the two words! Using both means a dialect.
What you said was equivalent to saying that “Jim Carrey speaks Manc with an American accent”. I/O error, ok?