Compared to the fellow Japanese people I play with here, I guess I am quite loud on the court, either expressing my joy or regret as the game goes on. But how much is one aloud to shout out and make noises during the game? Take for example doubles, when your partner is receiving a serve, and you tell them that it is going out, so they don't go for the shot, the shuttle lands out, and your team gets the point? Is that ok?
I'm like you, tending to be the most vocal one on the court or even in the whole gym(!), especially when I'm really getting into a rally or game. . I think it's ok as long as you don't do it when it's your opponents turn to hit the bird. So the answer is is yes to your 2nd question.
What visor said is correct, you can shout as long as the shuttle is not on your opponent's side. You can say OUT, or yell MOVE UP, or YOURS, or some other tactic to your partner. You can shout as long as it's not distracting to your opponent. And if you win the point, you can shout as long as it's not like excessive celebration where you rub it in your opponent's face. With an umpire, it's mainly up to their choice, but if it's just open gym and your opponents request you to take it down a notch, just do them the favor. Screaming while you smash will help you smash stronger too (if done correctly, because you are exhaling while you smash, you can look around on the forums or google for more information on this)
Thanx CantSmashThis. Although I prefer to keep quiet when I smash strongly and then scream loudly when I next do a dinky drop!
^^^ Actually come to think of it, is that allowable? Or would that be considered a distraction? I've seen it done a few times by Koo and Tan, Cai, and Jung; and the umpires never faulted them.