Sorry to take the points, but I will help you with the speeches.
A casual format can use more relaxed words, while staying away from internet slang like “lit”, and “no cap”
A formal audience is going to be a bit more, well, formal.
And finally, and academic format, without context, seems to be for an educational audience, like something you would turn in as school work. Hopefully this helped a little, because you can’t ask somebody online to write three paragraphs for you.