The Greenbond from Arcana Evolved is able to Speak with nature Spirits.
You could tweak a standard character class and add a similar feature to it, like Speak to the Dead or similar ability for a Paladin or Cleric of the appropriate deity, as a particular Domain ability or otherwise.
Don't hesitate to adapt existing materials to your needs.
Shaman? I know I have it in a book here somewhere since I had a PC concept that would have used it (but never did) but danged if I can remember what book.
I think it's the OA shaman. When Wulf played one in my game, we made his sphere spells be granted from spirits, and he could see and talk to them. I'm not sure how much of that is RAW and how much we did as house rules.