how they get all that smarts inside that tiny little head, but they are yet another thing that demonstrates the thing about brains isn't really they're size. of course, a lot of "speech" may be mimicking sounds without fully understanding their meaning, but then it seems to me, that a hell of a lot of humans do that too.
Ravens are really cool and highly intelligent birds. Many people don't realize they can mimic human sounds and voices. Or talk, in other words. Most people are blown away by this, because many believe that only the tropical colorful birds are the ones that can talk.
There's a difference between mimicking a sound and talking. Not saying these birds aren't exceptionally bright but its not like they can converse in a human language. They can just reproduce the sound of the word real good. And memorize what a word is used for, but so can every dog.
