I have many parents and coaches asking me what their goalies should be saying to their defensemen.
The first and most simple rule I tell all goalies is "say what you see, and keep it short".
In a conversation I had with Mike Richter he said the best player he ever played with was Brian Leetch because Brian always said whatever he was seeing. Brian always said what he was looking at and what he was doing. Even if you couldn't see him you knew exactly what was happening around him.
Another benefit to saying whatever you see is it keeps you in the moment. If your eyes and mouth are working together it is easier to keep your mind and body in unison as well.
Once a goalie starts talking there are a few basic guidelines.
Call out the rush. As a play moves through the neutral zone the goalie should always call out the numbers of the rush. 3 on 2, 2 on 1, 2 on 2, etc.
Identify open players. If a player is open say it and where on the ice. "Open far post", "Open high slot".
Screens. If you can't see let people know.
Forechecking pressure. One hard. Two hard. Time. Are all common phrases.
More complicated verbal commands should be discussed between coaches, players, and the goalies. This usually pertains to how to handle the puck in breakout situations.
Some common phrases are:
Wheel: When a dman has pressure and uses the net to cut off the forechecker.
Hard around: Dman rims the puck hard.
Reverse: Dman reverses the puck behind the net usually when under pressure.
D to D: D to D pass
Stretch or far blue: Refers to a stretch play when trying to catch a team in a line change.
To conclude what a goalie or any player really needs to do is act as a second set of eyes and you do that by saying whatever you are seeing.