Maybe it is more accurate to say that each person becomes aware of God's call in the existing situation and setting. Put most simply, God is calling each of us to be witnesses who proclaim the presence and power of God through all that we are and all that we do. God is calling each of us to tell others about God's love and forgiveness. God is calling us to be his spokesperson on earth. The message may be simple, but the ways we proclaim the message are as varied as the people who hear the call.
People hear the call and live it out in many ways including as a lay speaker.
That call, like the call to any other ministry, must be followed by preparation, practice and evaluation. First, each of us responds to God's call out of a sense of humility. God's calls to people are not in any order of importance. The call to lay speaking sets you apart as a lay speaker, but it does not set a status, rank, or privilege that is not shared by every other Christian who responds to God's call, whatever the call may be. Becoming a lay minister requires going down a path filled with many steps.