From Page 40 in Friend at Court
33. Claiming a hindrance. A player who claims a hindrance must stop play as soon as possible.
34. Talking when ball is in play.
• Singles players should not talk during points.
• Talking between doubles partners when the ball is moving toward them is allowed.
• Doubles players should not talk when the ball is moving toward their opponent’s court.
• When talking interferes with an opponent’s ability to play a ball, it is a hindrance.
For example, if a doubles player hits a weak lob and yells “get back” and the yell distracts an opponent who is about to hit the ball, then the opponent may claim the point based on a deliberate hindrance. If the opponent chooses to play the lob and misses it, the opponent loses the point because the opponent did not make a timely claim of hindrance.
For example, if a player yells after an injury or getting stung by a bee, this is an unintentional hindrance that would entitle the opponent to claim a let.