Are these senctences correct and is everything grammatically correct?

We're hella short. Everyone else is tall af/everyone else is hella tall.


By definition, slang is sub-standard English, so, in some circles, it is considered ungrammatical.


Yes, "hella" is an adverb modifying an adjective, but if you say it outside Northern California, you will sound very strange. It is one of those regional slang words that brand you, like New England's "wicked".

 AlpheccaStars's reply was promoted to an answer.