"She works as an interpreter between Swedish and English."
Translation:Hon arbetar som tolk mellan svenska och engelska.
But she isn't an English to Swedish interpreter. She translates into both languages as interpreter. Translators and interpreters in the UE work between 3 languages. Then you need to use 6 language combinations, if you don't want to use "between". 4 languages make 12 language combinations: SWE->GER, SWE-ENG, SWE-POL, GER-SWE, ENG->SWE, POL->SWE, GER->POL, POL->GER, ENG-POL, POL-ENG, GER-ENG, ENG-GER. Or you just say, that you work between Swedish, English, Polish and German.