Instructions for Speaking in Tongues

I Corinthians 14:26-28

26  How is it then, brethren? when ye come together, every one of you hath a psalm, hath a doctrine, hath a tongue, hath a revelation, hath an interpretation. Let all things be done unto edifying. 
27  If any man speak in an unknown tongue, let it be by two, or at the most by three, and that by course; and let one interpret. 
28  But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God.