The paper presents some aspects of an ongoing project aimed at the development of technologies for digitization of Bulgarian folk music and building a heterogeneous digital library with Bulgarian folk songs presented with their music, notes and text. This digital library will provide both digital preservation of the sound recordings, lyrics and notations of Bulgarian folk songs and a possibility for new interpretations of the archaic Bulgarian folklore heritage. Some facilities of the search engine under development to implement various types of search and access to the library resources are analyzed in the paper. The emphasis of the discussion falls on the tool provided for semantic search in the lyrics of songs.