Yeah, sometimes I'm grateful for learning some Japanese, and other times I can't stand it since you start realizing just how bad most localizations are.
I noticed during my playthrough of the fort defense that Leon refers to one of the characters with a JP oneechan suffix instead of the Romanized equivalent. I can't type the proper words since the forum thinks IME is a URL.
Edit: I only saw one other one where Leon calls Claude oniisan in JP in...