i use gtranslate to translate Bulgarian to English, generally its ok only problems i have found is when original document is written by a Bulgarian with no grammar who joins words together.
bulgaria is one of the few European Countries which doesnt have a country wide education system so dialects creep into written language borrowing words from russian, romania, greece, serbia and turkey.
european documents written in bulgarian translate 100% but local newspapers are notoriously bad.
i know i can use chrome instead of firefox and often do but firefox allows easy access to orginal web address of newspaper arcticle