Apparently this turned out to be a false rumor but I heard it was because years ago, there was a temperamental king with a lisp and so to not offend him, everyone else adopted it lol.
I don't really want to know the real reason because that one makes me too happy.
When it is Castilian Spanish.
Oh. I don't speak Castilian. In gracias the c is lisped. I know that much.
Try looking for a translation dictionary with sounds