Polish language in Schindler's List

As per Wikipedia:

Spielberg occasionally used German and Polish language in scenes to recreate the feeling of being present in the past. He initially considered making the film entirely in those languages, but decided "there's too much safety in reading. It would have been an excuse to take their eyes off the screen and watch something else."

The quote originates from this interview with Susan Royal for Inside Film:

Susan Royal: Originally you wanted to shoot it in Polish and German and use subtitles. You didn't do that but you use a certain amount of German and Polish in the film.

Steven Spielberg: I had Germans speaking German and Poles speaking Polish only on certain occasions when I wanted to pretty much show what it was like and what it sounded like and then only let those moments come across in English where I had to make a point.

Susan Royal: Now that you see it, do you think that was a better decision than going with subtitles?

Steven Spielberg: Yeah, I think so. Because I wanted people to watch the images, not read the subtitles. There's too much safety in reading. It would have been an excuse to take their eyes off the screen and watch something else.