Tongue-speaking was a miraculous gift of the Holy Spirit limited to the first century. If you had the gift, there would be no doubt, because tongue-speaking was intended to be an amazing sign to convince unbelievers (
I Corinthians 14:20-22).
With the exception of the apostles and house of Cornelius (the firs Jewish and Gentile converts, respectively -
Acts 11:15-18), people only received spiritual gifts through the apostles laying their hands on people (
Acts 8:13-20; II Timothy 1:6; Acts 19:4-6). Without apostles today (
Acts 1:21-26; I Corinthians 15:7-8; Matthew 19:27-28), there is no way to receive these spiritual gifts. You can read more about the types of baptism discussed in the New Testament, including baptism of the Holy Spirit, here:
http://www.insearchoftruth.org/articles ... ptism.html
Furthermore, spiritual gifts were meant only to confirm the divine origin of the apostles' and prophets' message (
Mark 16:17-20; Hebrews 2:1-4). Once that message was fully revealed and confirmed as being from God, then their usefulness was over. Like a child growing and leaving childish toys behind, the mature church has left the fascination of spiritual gifts behind (
I Corinthians 13:8-13). This was foretold even in Old Testament prophecy concerning the church, that miraculous gifts and prophecy would cease (
Zechariah 13:1-6).
Friend, Pentecostal groups that teach the need for modern tongue-speaking and baptism of the Holy Spirit are in great error! I would encourage you to find a group that is teaching all of God's truth, and not just part of it (
Galatians 1:6-8).