We have heard a lot of actors trying to sound German over the years. Sometimes native speakers aren’t available as actors or extras and it’s up to the producer to find actors who at least had some German in school. Or your screenwriter works with a language trainer/consultant to turn the German lines in the script into something that is easier to pronounce for the actors. To achieve more realism, actors could get help with the pronunciation from a consultant themselves. Having worked as a consultant on Australian WWI feature film “Beneath Hill 60”, I can guarantee you that this will improve your film, get rid of some stress on the set and therefore speed up the production. If your actors have problems with their lines, this can easily result in way more takes than your budget allows.
Or you end up with something like this example, which has been lifted from a popular TV show about a superagent who saves the world within one day on a regular basis. Both people in this scene are supposed to be native speakers, but it sounds like they are reading their lines from a piece of cardboard stuck on somebody’s back. Even if you don’t speak German you will find it a little hard to believe.