Does Tashas Hideous Laughter’s applies to prone target?

@JeremyECrawford Tashas Hideous Laughter's wording implies the incapacitated effect only applies if the target is made prone, is this right?

— Samuel Rodda (@QueerSeer) March 2, 2016

Failing a save against Tasha's hideous laughter means you're incapacitated even if you can't fall prone. #DnD https://t.co/XAjXDA6m8i

— Jeremy Crawford (@JeremyECrawford) March 2, 2016