A person who speaks in tongues has full control over his actions. Such a person can choose to remain silent, and should do so if there is no one to interpret. Yet it will not be wrong for him to speak in tongues in his private worship. Unintelligible speaking is inappropriate only in the worship service, where all activities must serve to build up the church as a whole.
28 But if there is no one to interpret, let each of them keep silent in church and speak to himself and to God.