Flashbacks to my driver's ed teacher in highschool who would say adverbs correctly then correct himself by saying it again without the -ly. This drove me insan

Flashbacks to my driver's ed teacher in highschool who would say adverbs correctly then correct himself by saying it again without the -ly. This drove me insane. And no I haven't noticed this generally in US english speakers. I would assume some negative things about people who drop the -ly from adverbs.