This seems to be something that has created some confusion and myths. First off, if you open your mouth and say words, the ghost will hear them. Unless you actually mute your microphone, the game is always listening. Even if you are using push to talk, and you're not pushing to talk, it is possible that the ghost will hear you.
The next most important thing to keep in mind is the following: Using the name of the ghost is likely to accomplish only one thing - getting you killed. When the ghost gets angry it is less likely to interact with your equipment and is more likely to hunt. And when a ghost hunts it isn't hunting for a toy to interact with, because what it wants to interact with is your skull and it wants to interact with it by crushing it. So if you want to stop the ghost from hunting using a Crucifix, go right ahead and use its name. Even better, hurl curse and swear words at it. That works better than its name!
So here is another thought. You're chatting with your team while you are looking for the ghost and drop the odd F bomb or other curse word. Yay... you're angering the ghost right there. Like the game says 'Watch what you say, the Ghost is listening'. That's not a joke!
Also keep in mind that if you ask the ghost 'Carol Martin, where are you'? All the ghost hears is 'Carol Martin' (its name in my example here) and the Ghost doesn't think oh, give 'em a sign. It thinks 'Rage Kill'. This will not help you.
So talk to it by just asking your question or making your statement. 'Give us a sign', 'Where are you?' or 'Are you here?' Even without a Spirit Box or Ouija Board these things work. And yeah, they even work with the lights on!
It is also true that once you walk into the location and are looking for the ghost you can start asking for a sign or asking it where it is hiding. There is no magical timer that says you have to wait any amount of time. You just have to be in the building.
And when it hunts, it is still listening. Do you really think the ghost is going to listen to everything you're saying while its chillin' and doing nothing and then ignore everything you say when it's trying to find you and kill you?