The book is a silly concept where the family dog begins to speak after eating some alphabet soup. It is a common fantasy for children and the silliness of his actions and words once he has the power to talk will have your child on the floor giggling.
The one thing to note is the importance of the stressing the correct way to talk to someone who is bothering you (i.e. not yelling shut up). It is important to note to your child they treated the dog poorly. Most children will get it on their own but it is something to point out so they don't think they can just yell "shut up" at the dog or a human that is talking too much. That is the most common complaint I hear about the book.
I highly recommend this book to parents.