There are websites where you can search for all kinds of doctors in Germany. Here is an example for Lower Saxony:
You have to set the filters to "Fachgebiet = Innere Medizin" and "Ort = Osnabrück". Tick the box that says "Kassenpraxen".
You will get a list of all internists in Osnabrück. You can click on "Details" to get contact information and to find out which languages they speak.
I hope this helps!