The Reign Of Winter
Bonus Languages: A druid’s bonus language options include Sylvan, the language of woodland creatures. This choice is in addition to the bonus languages available to the character because of her race.
A druid also knows Druidic, a secret language known only to druids, which she learns upon becoming a 1st-level druid. Druidic is a free language for a druid; that is, she knows it in addition to her regular allotment of languages and it doesn’t take up a language slot. Druids are forbidden to teach this language to nondruids.
Druidic has its own alphabet.