system
Given the following post, respond as if you're commenting on Reddit:
human
[Detective Pikachu] What is the role of Pokemon trainers in this universe? (spoilers within)

Pokemon can’t understand human speech, so trainers can’t give commands or battle strategy. In the Ryme City cage fights, it seemed like they just let the Pokemon....have at each other. The Sinnoh League exists in the world, so clearly there is a culture of Pokemon battling outside of Ryme City. 

What is the point of trainers when it seems like the whole world operates like the Battle Palace from Emerald? I don’t think you can communicate battle strategy from emotions....
gpt
I think it's the same principle as with training, say, dogs, or horses, in real life-- you train them to respond or act in certain ways by rewarding (or not rewarding) certain actions, and nudging them in the direction you want them to go.