With only a short time available in church, speaking in tongues isn’t the best way to use the time. Rather speaking what the Bible says (prophesying) is much more beneficial to the body. Speaking in a foreign language shows off the speaker’s gift because few understand him.
For anyone who speaks in a tongue does not speak to men but to God. Indeed, no one understands him; he utters mysteries with his spirit. But everyone who prophesies speaks to men for their strengthening, encouragement and comfort. He who speaks in a tongue edifies himself, but he who prophesies edifies the church. I would like every one of you to speak in tongues, but I would rather have you prophesy. (1 Corinthians 14:2-5a)
He who prophesies is greater than one who speaks in tongues, unless he interprets, so that the church may be edified. Now, brothers, if I come to you and speak in tongues, what good will I be to you, unless I bring you some revelation or knowledge or prophecy or word of instruction? (1 Corinthians 14:5b-6)
Even in the case of lifeless things that make sounds, such as the flute or harp, how will anyone know what tune is being played unless there is a distinction in the notes? Again, if the trumpet does not sound a clear call, who will get ready for battle? (1 Corinthians 14:7-8)
So it is with you. Unless you speak intelligible words with your tongue, how will anyone know what you are saying? You will just be speaking into the air. Undoubtedly there are all sorts of languages in the world, yet none of them is without meaning. If then I do not grasp the meaning of what someone is saying, I am a foreigner to the speaker, and he is a foreigner to me. (1 Corinthians 14:9-11)
So it is with you. Since you are eager to have spiritual gifts, try to excel in gifts that build up the church. For this reason anyone who speaks in a tongue should pray that he may interpret what he says. For if I pray in a tongue, my spirit prays, but my mind is unfruitful. (1 Corinthians 14:12-14)
Even if there is an interpreter present, its better by far to tell others what God has taught you about Jesus and how it has made a difference in your own life.