At Pentecost, the gift of tongues enabled believers to proclaim the gospel in real, known languages they had not learned. Paul lists tongues among the Spirit's gifts, while also instructing that it must be exercised in order, with interpretation, and never above intelligible teaching that builds up the whole church.
In Acts 2, tongues appear as actual human languages, allowing the gospel to be understood immediately by people from many nations without a language barrier. Paul confirms tongues as one of several genuine gifts distributed by the Spirit for the church's benefit, but in 1 Corinthians 14 he places clear guardrails on its use in public worship: it should be interpreted so the whole congregation can be built up, exercised in turn rather than chaos, and never elevated above intelligible teaching and prophecy, which edify the church far more directly. Whether or not the specific gift continues in exactly its New Testament form, the underlying principle stands: any spiritual gift, including tongues, is meant to build up the church in an orderly, understandable way, not to draw attention to the individual or create confusion.
These themes are best read through the whole testimony of Scripture, emphasizing God's self-revelation in Christ, the active ministry of the Holy Spirit, and the restoration of the whole person. Bible study should lead to a changed life, compassionate service, and a clearer picture of God's loving character.