This is an endless debate as Tama says its a personal matter but the final authority is the Word of God this is the truth of it the rest is mens own beliefs now it is each to your own as to whether you will take Gods truth as fact or hang on to your teaching of men.First lets understand there is a Holy Tongue it was spoken by all before the tower of Babel and its possible some may have a gift of speaking it. However it is only understood by God as stated in Cr 14:2Speaking in this tongue benefits only self as no one understands it.Cr 14:4 He that speaketh in an unknown tongue edifieth himself;but he that prophesieth edifieth the church. What does this mean? Prophecy is the greater gift. If God see's fit to interpret to someone what is being said in this Holy tongue it will be a prophecy to share with and benifit the church. CR.14:5 I would that ye all spake with tongues(He would like it if all had this gift, but he would rather we have the gift of understanding it) but rather that ye prophesied: for greater is he that prophesieth than he that speaketh with tongues, except he interpret, that the church may receive edifying. CR.14:6 Now, brethren, if I come unto you speaking with tongues, what shall I profit you, except I shall speak to you either by revelation, or by knowledge, or by prophesying, or by doctrine? Another words speaking in tongues is worthless unless it is interrupted so that all understand what is being revealed.(just as in Acts all understood)Cr.14:9 So likewise ye, except ye utter by the tongue words easy to be understood, how shall it be known what is spoken? for ye shall speak into the air. You speak nothing but to the air unless God has granted you the gift of prophecy/revelation of this tongue.Now how do we discern a true prophet/prophecy? It will be 100% true and accurate. Just as the prophets in the Bible. So unless you can reveal what you are prophesising in this tongue and it is 100% true an accurate and benefits the entire church.It should only be spoken in prayer between you and God. As it edifies only self.Conclusion: if you pray in tongues only God I said ONLY GOD can understand it. So it is a waste of time to speak it in public. without understanding of what you say.The above is not my opinion but what scriptures says this can not be debated for it is Gods word on it.My question is if it is not understood how do you know it is from God? as you do not know what you say. So unless you have the gift of prophecy to understand what you are saying.I would say be very careful when/if you speak it in public.