While English isn't the first language for most Cypriots, most can speak it very well. This has a great deal to do with the fact that Cyprus used to be a British colony, and also with the number of foreign UN soldiers that live on the island. Because of this, signs and just about everything written offers an English translation. The other language you hear very often in Cyprus is Russian. Cyprus is a very popular place for Russian tourists, so you'll find many restaurants catering to Russian tastes, and a great deal of Russian on signs all over the island.
The native language in Cyprus is a bit more complicated. In the past it was a mix of both Turkish and Greek, however, after the problems during the 1960s and 70s there is a great divide. Today you'll find that just about everybody south of the buffer zone speaks Greek, and almost everybody North of the buffer zone speaks Turkish.
Currency wise, Euros are probably your best bet. To the south of the buffer zone you’ll find everybody uses Euros, while to the north of the buffer zone most uses Lira. My experience has been that people on the southern part of the island are far less likely to accept Lira, and the people on the northern part of the island are happy to accept euros.