Indiana couldn’t warn the natives about Belloq because he didn’t know Hovitos. In the next shot he redeems himself by shouting, “Start the engine, Jock!” to warn Jock about the natives. This is a subtle nod to his, and Jock’s, command of the English language.
Although set in Nazi Germany, no one speaks German, aside from the occasional “ja” und “nein.” This is a subtle nod to Taika Waititi writing it for an English speaking audience, who do not understand Deutsch.
The addition of “shin” in the title has many meanings, which is clever wordplay on the writer’s part. In Japanese it can mean things like “new,” “true,” and “god.” In English it refers to the part of the body that connects the ankle bone to the knee bone, just like in the hit song Dem Bones (“shin,” in English, is pronounced “leg,” the s is silent).