Wikipedia
Bellsybabble
Bellsybabble is a fictional language of the Devil, which he makes up as he goes along. Writer James Joyce mentions it in the following postscript to a letter (containing the story now known as "The Cat and the Devil"), which he wrote in 1936 to his four-year-old grandson:
The name "Bellsybabble" is a pun on Beelzebub, "babble" and Babel. Bellsybabble has variously been called a poly-language, a pluridialectal idiom and a ludic creation.