User blog comment:Miskos3/Fairy Tail Chapter 334: Sin and Sacrifice, Review/@comment-203.87.139.100-20130607155617/@comment-7418318-20130607160701

Even Acnalogia can speak the Human language, he just chose not to converse with the "bugs".

That they CAN speak our language is clear, I was just wondering why they use it even when speaking among each other. Maybe it really is somehow tied with the Dragon Manipulation magic.