We know there is nothing impossible for God to do. But it seems there is something figurative about Numbers 22:28 when it says the Lord opened the mouth of the donkey.
Then the Lord opened the mouth of the donkey, and she said to Balaam, “What have I done to you, that you have struck me these three times?” (ESV)
Did the donkey talk plainly or something? If it was so, then why is the Bible silent about other instances of animals that talked before and after the case of Balaam? The experience of Noah in the ark is the most likely case where we could have read of animals that talked before the case of Balaam.