Many different languages are spoken in Europe. Most are members of the Indo-European language group which also includes the main languages of Iran, Afghanistan and much of the Indian subcontinent. Major subgroups found in Europe are:
English proficiency varies greatly across the continent, but tends to increase the further north you get, in the Benelux and particularly Scandinavia almost everyone can communicate in English with varying degrees of fluency. German-speaking areas in the middle also have good levels of proficiency. In the south and east you'll often be out of luck, especially outside major cities and tourist centres. Speaking one of the Romance languages may be of some use in Portugal, Spain, France, Italy and Romania, while the same is true if you speak one of the Slavic languages in the East.
Russian may be spoken as a second language in the formerly communist countries of eastern Europe, particularly by the older generation, and is still widely studied in Belarus, Ukraine, Moldova, Armenia and Azerbaijan. German is also a useful foreign language in Eastern Europe. English is however gradually replacing Russian as the main foreign language in much of eastern Europe.