system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How do they sync a voice to cartoon characters?

How do they sync up a characters voice in a cartoon?  I don't me CGI stuff, I am asking about the hand drawn material.
gpt
Storyboard artist for a 2d kids show here, 

The dialogue is recorded first. We listen to it while working out the acting and staging and draw the important poses and expressions that feel natural to the performance of the voice actor. This is called "blocking". From here the board artist might add some more detailed acting (as you do in television cartoon production, to make for a faster animation process), or if you work in full length features, pass it off to the animator to figure out the really detailed expressions and mouth shapes.