Book swallower 

Somebody who studies all day, similar to a nerd but it arrives to a point that they “swallow books”.

yo cuz, that chick is a book swallower - watch out.

Book swallower by scooge February 24, 2023

Swallow a joke book 

To describe when a person is humorous for a lengthy period of time.

Everything that guy said was funny, did he swallow a joke book or something?!?

Also can be replaced by 'dictionary' for someone who says words that no-one understands.

Swallow a joke book by alimccarley October 9, 2008