Why can't animals speak?

You might think these bears look like they are telling each other a joke,
but they can't be, can they?  

This morning on my way to school, I was talking with my mother about school and asked her if there were any different ways of learning.

She suggested a good way was to think of things I'd like to know more about and explore, like I sometimes do on this blog. So I thought of a question I would like to explore and here it goes:

Why can't animals speak?

I'll be investigating this and will let you know what I've found out about it here in a few days.

In the meantime, if you have any interesting ideas or things to share, please leave a comment!