You can ,learn to speak and comprehend Bulgarian, very useful for your next trip to Sofia.
This course is an introduction to the language and assumes no prior knowledge of Bulgarian or other Slavic languages. Each unit is divided into three parts: Basic Sentences, Notes, and Drills, with review units also included. Using both the book and audio, the student is gradually moved toward proficiency in spoken Bulgarian and its grammar. Level Two continues the first level for students who want greater proficiency. Level One comes with 11 CDs and a book; Level Two with 6 CDs and a book.
Video for traveling in Bulgaria.