It is an effort to imitate the AAVE dialect of the Harlem-born Jackson brothers, the characters Todd Bridges and Gary Coleman played on the show, via spelling.Why is "diff'rent" spelled this way? Is the first e not pronounced? Is it a common pronunciation/spelling of this word?
I agree that this was the intention; what's funny is that, as others have pointed out, above, this pronunciation of different is no diff'rent than the Standard American English pronunciation. It's not a formal pronunciation, but it's certainly not unique to AAVE. It's as strange as if they had spelled The Fresh Prince of Bel Air as Th' Fresh Prince 'a Bel Air - as if that weren't the Standard American English pronunciation (or for that matter Amon 'n' Andy - as if any but the most persnickety American English speaker would ever say "Amos and Andy"). These seem to be attempts to make African Americans more exotic than they actually are.It is an effort to imitate the AAVE dialect