Prayer. We've all done it at one time or another. Often it's at a point of crisis or desperation when all else has failed or when a situation is totally out of our control. At other times it's in moments of extreme emotion - an outburst of joy or excitement or a cry of grief or heartbreak or confusion. Sometimes it's routine, sometimes it's spontaneous. Sometimes it's read from a set book, sometimes it's made up on the spot, off the cuff, out of the moment.
The one common thread through it all is that prayer is communication with God. In fact, that's the dictionary definition of Prayer:
the act of communication with a deity.
To some, that definition doesn't come as much of a surprise, and maybe you were hoping for a more detailed and in depth exposition of what prayer is, but I think that there is a beauty in that simplicity...Prayer is communicating with God.