I don't know if the article makes this clear, but it if they are just using ASL, the benefit there is that they've been communicating via ASL their whole lives

I don't know if the article makes this clear, but it if they are just using ASL, the benefit there is that they've been communicating via ASL their whole lives and understand it "natively". It's also a language that was refined over time to communicate things quickly and concisely. Other teams do develop their own language, with both verbal and hand signal components. However, I'm not sure high school football coaches are necessarily adept at making new languages, sure maybe it is good enough for what they're doing, but is it as robust as ASL or English? Of course not. Then, the players need to take time to learn it, if they ever even fully grasp it. Then, the players will come and go, so once a senior, who probably fully gets it leaves, the coach is left with a bunch of new players they have to teach - for this reason, the language is hard to refine. For all of these reasons, the team using their native language has an edge in communication. This is probably better at the pro level since a player on each side has a direct line in their helmet from the coaches and the players stick around long enough to master the new language. Overall, though, I think this line in the article is downplayed: The coach attributes the turnaround to rigorous conditioning and an especially talented cohort of players, some of whom have played together for years at lower levels. It's a great human interest story to talk about turning a perceived disadvantage into an advantage, but it sounds like, deaf or not, this particular group of players shows great teamwork and a great work ethic.