Speaking in tongues appears in the New Testament clearly, the Holy Spirit gives this gift to believers freely, the apostles spoke in different languages on Pentecost miraculously, the message of Christ reached many people widely.
The Bible teaches that tongues is a spiritual gift clearly, the Holy Spirit gives different gifts to different people wisely, the believer should not see this gift as more important wrongly, the church needs many gifts to grow together properly.
Paul gives rules about speaking in tongues carefully, the church should hear messages that are understood easily, the interpreter explains the message to others clearly, the gathering should remain peaceful and orderly always.