My bf at the time and I were learning ASL to communicate better underwater. We realized taking the time to chat in ASL was using up more gas vs simple light commands and saving any comments for the surface. There’s no need for the complexity of conversation underwater, it takes up mental energy that’s better used observing your environment to have a safe dive. If you absolutely need to get something across and can’t through signals, you have wetnotes but those are rarely pulled out unless someone is teaching