The Druidic Language
All druids have one thing in common: knowledge of the Druidic language, which druids receive as a bonus language upon taking their first level of the class. What does this mean? Why would an Eldeen Greensinger and a Talenta mask-weaver speak the same language, not to mention the hermit who has never encountered another druid? If the Gatekeepers were trained by a dragon, why do they know Druidic instead of Draconic?
Druidic is not a normal language. You don't learn Druidic in the same way that you'd study Sylvan, and even if you know it, you can't teach it to a friend any more than you could teach her to cast detect snares and pits. As you master your first level of druid, you learn many magical mysteries. You learn how to speak with animals, how to calm them, and how to hide from them. You unlock the secrets of fire. You learn to mend flesh with a touch, and how to ask the plants to entangle and trap your enemies. These are just a few of your secrets, and the Druidic tongue is another. Many druids believe that it is the first language -- the primal language of Eberron herself. Some claim to have found Druidic inscriptions carved in the sides of mountains or written in the drifting clouds; the DM will have to decide if these tales are truth or fancy.
http://www.wizards.com/default.asp?x=dnd/ebds/20051017a关于学Dru的语言,这个可以参考一下。