Finding a cinema which offers movies in their original languages can be challenging in Berlin. But there are solutions! Even if you end up in Potsdamer Platz planning to enjoy a blockbuster in English there is an alternative 20 meters away, still in the Sony center. You will find the kino Arsenal underneath the Filmmuseum which hosts several film festivals, retrospectives in many languages, not to mention the very comfortable seats.
Take the Kino International on Karl Marx Allee at U-Schillingstrasse, it is a bit far from everything and films are shown mostly in German, but not always! Often in the late evening, meaning after 22:00, films will be screened in original languages.
The building has a cubic shape from the outside, it is impressive. You have to see it. It is good to arrive a bit in advance, not because of your reserved seats but in order to spend some time at the bar and look at the ceiling chandeliers. It is kind of a Berghain impression, high ceiling, you feel tiny, in winter you have no clue what floor you are standing on. Let’s call it a spacecraft. The theater has a giant screen and nice old-school seats with vintage air conditioning system right under your feet.