Okay kiddo, imagine you and your friend are talking about pizza. You say you like pepperoni pizza, and your friend says they like mushroom pizza. You both talk about why you like your favorite toppings, and that's called convergent discourse because you both are trying to understand each other's opinions and maybe even find some common ground.
But sometimes people talk about different things and never really listen to each other. It's like they're speaking different languages. They might even argue and get really upset, but they never really understand each other.
That kind of talking is called non-convergent discourse. It's like talking in circles or just repeating the same things over and over again. It's not very helpful because neither person is really learning anything or making progress towards a solution. It's like arguing about whether unicorns are real or not. It's not a conversation that can ever really go anywhere because there's no common ground.