Theists who speak with God

[ignoramus]

I was just wondering, when a theist communicates with God, is there any etiquette which needs to be followed.
EG: I know that you can initiate a conversation with God through prayer, but if God needs to tell you something, does he just say it in your head?
If God can hear your thoughts, why do people pray out loud? (I know he's old, maybe he's a little deaf and needs to lip read?)

I mean what if you're in the middle of sex or listening to motorhead with your headphones in? Does your music just cut out or does he have to shout a bit so you can hear him? I know I sound a bit naïve but being a tech nerd, I'm just fascinated with technical details, that's all.

Someone please help this misguided but well meaning heathen ...