Some animals can mimic the sounds of human speech. Not just birds—there have been cases of great apes and whales demonstrating vocal learning! But animal communication is different from language.
Language is a system of spoken or written communication. It has words and sentences. Rules of grammar and structure. We know that dolphins can communicate with each other through clicks and whistles. But there isn't concrete proof that these sounds are words and sentences.
Animals can use both verbal and non-verbal communication to "talk" to each other. Non-verbal communication includes gestures, body language and facial expressions. Animals from different regions of the world have different "dialects." But nothing has been discovered to be as complex and creative as human language.
What's your favourite animal? If you could talk to them, what would you ask? Maybe one day you'll get to study them in the wild and find a way to communicate!