THE INITIAL PHYSICAL EVIDENCE OF THE BAPTISM IN THE HOLY GHOST
The baptism of believers in the Holy Ghost is witnessed by the initial
physical sign of speaking with other tongues as the Spirit of God gives
them utterance.
Acts 2:4
The speaking in tongues in this instance is the same in essence as
the gift of tongues, but is different in purpose and use.
1 Corinthians 12:4-10, 1 Corinthians 12:28