When Batman kicks butt, he doesn't need a lot of dialogue to dump the dumbdumbs. At its best animation is all about action and movement; it explores space and time. You want to show, not tell, your story. There are cartoons with no dialogue at all! But three dialogue blocks per page and no more than three short sentences per block are normal. Generally, in animation dialogue should be used only after you've tried all other methods of communication. Silence can accompany discoveries, revelations and deep emotions. Dialogue is used to reveal the characters. It provides direction, moving the story along and advancing the plot. It discloses information. It provides conflict. And it sets the spirit or mood of the story, whether it's a comedy or drama.