"Does the interpreter speak Swedish?"
Translation:Talar tolken svenska?
"Talar" is actually more appropriate in this case! "Talar" may be antiquidated, but in the case of describing what language a person speaks (Jag talar svenska - I speak (the) Swedish (language)), it's perfectly fine.
You can however use "pratar" and still get your meaning across. The context is clear enough to indicate that it's meant as "speaks" rather than "is speaking (right now)".