Pokemans Episode 2- What happens inside of a Pokeball?
No one really knows what happens inside a Pokeball. This is just a guess, but what if two or more Pokémon were (separately) in their Pokeballs at the same time, maybe they could interact with each other, or even play with each other. Pokémon can understand each other, but humans can't understand Pokémon. That's the only reason you can understand what the Pokémon are saying in this video. Because its Pokémon interacting with each other.