speaking in tongues (unknown languages) was a concern of the Corinthian church because the use of the gift had caused disorder in worship. Speaking in tongues is a legitimate gift of the Holy Spirit, but the Corinthian believers were using it as a sign of spiritual superiority rather than as a means to spiritual unity. Spiritual gifts are beneficial only when they are properly used to help everyone in the church. We should not exercise them only to make ourselves feel good. See also the second note