what is there to do in bulgaria

[jamiemirror]

About language barrier - this is not so big problem here :-)
If you choose good hotel/bar/pizza/restaurant - expect the English-speaking staff too. Most young people will speak English acceptable.
About the climate - just enjoy the summer here :-) Get an ice cream, drink fresh beer (there are breweries in Plovdiv). I recommend you all the grilled food (mostly unobtainable outside Bulgaria/Serbia/Turkey area), fresh fruits and vegetable salads - Plovdiv is agricultural region also. It will be waste of time just sitting in hotel room - I think :-)