Speaking in an unknown language

Scripture references

1 Corinthians 12:10 (ASV 1901)

10and to another workings of miracles; and to another prophecy; and to another discernings of spirits: to another divers kinds of tongues; and to another the interpretation of tongues:

1 Corinthians 14:2–4 (ASV 1901)

2For he that speaketh in a tongue speaketh not unto men, but unto God; for no man understandeth; but in the spirit he speaketh mysteries. 3But he that prophesieth speaketh unto men edification, and exhortation, and consolation. 4He that speaketh in a tongue edifieth himself; but he that prophesieth edifieth the church.

Stories

After leaving a Bible study meeting on the early believers receiving the gift of the Holy Spirit and speaking in tongues, Maryam wanted it for herself and received the gift later that day in her room.
Jackie Pullinger speaks in tongues after an encounter with other believers.
Ah Tong was desperate to get off drugs. When he asked Poon Siu Jeh for help, Poon introduced him to Jesus and to some men who had been in jail with Ah Tong but are now believers in Jesus. Ah Tong accepted Jesus after listening to their story, he received deliverance, peace, joy and smiled like never before.
One night when Winson accepted Jackie Pullinger's invitation to come worship God, Winson who was fighting his addiction to opium and was only beginning to soften to the message of Jesus was filled with the spirit that he began to pray in Chinese and then in tongues.
Craig Keener had a most amazing experience in the presence of God two days after his conversion and was filled with the Holy Spirit and the gift of speaking in an unknown language. For over two hours Craig worshipped the Lord in this strange language and was edified.
After Gene prayed for Nicky Cruz to be baptized by the Holy Spirit, Nicky broke into tongues and went on to worship God in an unknown language for two hours, completely oblivious of the meeting coming to an end.
When Roberto who was an ex-convict and drug addict heard Nicky preach about the Holy Spirit and the power He gives, he rushed forward to receive Him into his life when the invitation was made. And the result for Roberto was not only speaking in tongues, but also, deliverance from drug addiction.
Neda was only 12 years old and lost. She was trapped in addiction to alcohol and promiscuity; she hated her family. But as Neda listened to other kids with problems worse than hers, and how Jesus was transforming their lives, she wanted the same thing for herself. And one day, when she finally opened her heart to God in prayer, He met her powerfully.
A woman who was possessed with evil spirits was prayed for by a man who spoke in an unknown language. Her deliverance was complete and she went on to become an evangelist sharing the testimony of her deliverance.