A rooster sounds like a rooster wherever it lives. A cow sounds like a cow in every country. So shouldn't we all use the same words for animal sounds no matter what our language? Imitations of sounds don't have to follow rules, but words for sounds do. Here's the scoop on why the same rooster might say cock-a-doodle-doo, kokekokko, or ü-ürü-üüü.