Few people in Ukraine speak English so some knowledge of Ukrainian (or Russian) will go a long way. The situation in the service industries is improving, but you can never count on locals speaking or understanding other languages. Both Ukrainian and Russian are written in the Cyrillic alphabet with very few concessions to those who cannot read it. Learning the 30+ letters of each alphabet (there are only a handful of differences between them) will save you a lot of deciphering time.