Sithis of Fangwood |
While Jeraa is correct, I can see one sensible caveat (for home games, at least).
Many magical beasts (and some polymorphed creatures, like Wildshaped Druids) are capable of communicating with animals similar to their kind.
If you're effectively speaking the same language as they'd be speaking, I don't see why cross communication wouldn't be possible.
Otherwise it'd be super easy to use a 1st level spell to effectively detect whether an animal was natural or not.
But, technically, as magical beasts and polymorphed creatures aren't "animals", the spell would not work on them.