One of my dive buddies brought up the idea of using full face masks a few years ago. His idea was, it would be so much easier to communicate if we could just talk without a reg in the way. I thought about it a bit, and agreed that it would be easier to communicate, but disagreed that that would be a good thing. I'm not down there to chitchat man, part of the experience is to just shut up and chill for an hour. He was like, you're right, come to think of it, I don't want to talk to you the whole time either!
It's very important to have the safety signals down pat, and crystal clear. Share air, down, up, hold this depth, turn dive (normal), abort dive (emergency), stop, OK? OK, boat, truck, pressure gauge and numbers, which way?, this way, follow. These are all pretty standardized, but it's worthwhile to go over them before diving, especially if you're with an unfamiliar buddy, or any member of the buddy group is a little new, or a little rusty.
I do agree that the critical thing is to ensure that you have somebody's attention first, then signal very slowly. Like, really slowly. Also, if you are wearing black gloves over a black wetsuit, understand that it will be very hard to see your hands and fingers. Consider bright gloves or a bright wetsuit to prevent this problem.
Besides the safety stuff, my dive group likes to get creative with hand signals. It can be fun to just make something up and try to mime the idea to your buddy. A few of the things we've gotten comfortable with are:
- "I don't understand": exaggerated shrug
- "I think / I guess": pointer finger tapping at your temple, confused expression
- "I understand": pointer finger tapping at your temple, understanding expression
- "Nevermind": palm initially facing them, and rotating wrist to palm down. Like throwing something away
- "No": pointer finger up, moving or rotating side to side
- "Yes": fingers pinched to thumb, facing them, wrist bending up and down. Like a nodding head
Armed with these techniques, you can express a wide spectrum from confusion to certainty, and feel confident in your ability to tell somebody whether or not you understand their made up on the spot BS hand signals