Discover the Bulgarian Language
If you're learning Bulgarian you may very well want to get an overview of the language, some of its unique features, geographical information about native speakers as well as loads of information on grammar, linguistics, history, diaspora and general language structure.
All of this and more is available in Wikipedia's Bulgarian entry. There are also some interesting links at the bottom which take you to further resources to explore and learn about the language of Bulgaria.
Don't Miss the Bulgarian Category Page
This may seem pretty obvious, but many people overlook reading the Wikipedia entry! Plus, most don't know about the related and useful Wikipedia category for the Bulgarian language, which takes you much deeper into the language.