Play has to stop in order to bring on a substitute, whether it be a goalkeeper or an outfielder.
It has to be the goalkeeper.
They try to stop the other team scoring, they defend the goalkeeper and the goal.
a save can be anything from a diving stop to a simple catch
No. In hockey, you can substitute without a stoppage in play. In football (american soccer) you need to wait for play to stop.
A soccer player kicks a ball into the opposing team's goal. A goalkeeper will try to stop this from happening
If you just want to be goalkeeper with out a desperate feeling in you, you most likely will never be an excellent goalkeeper. That's the truth. But if you have a feeling of desperation, try it. Most people stop and quit, and some keep going until they're professionals of the world.
Always. Even if the whistle was accidental, play must stop.
There are two answers to this question. First, if you're wanting to know about a substitute coming from the bench to play in the game, then the goalkeeper is treated the same as any other player: both players will be cautioned at the next stoppage of play, and if the incoming substitute interferes with play or the referee decides to stop play for this infraction, the opposing team is awarded an indirect free kick. If an outfield player switches positions with the goalkeeper (probably switching jerseys and gloves as well) without the referee's permission, the referee will allow play to continue and caution both players at the next stoppage of play. Note that the player wearing the differently-colored jersey is considered to be the goalkeeper, and if that jersey is worn by another player, that player becomes the goalkeeper with or without the referee's permission (but will still get a yellow card for his trouble), which means that the "new" goalkeeper can make a save without being guilty of a handling foul so long as he is clearly identified as being the one and only current goalkeeper for his team by virtue of the jersey.
The last rule by f.i.F.A was that if a penalty is there, then the penalty taker should take it with one run, he can not run and then stop and start again to fool the goalkeeper, if he does it he will get a yellow card.
The is no mandated gesture. The whistle is blown to stop play.