1 Corinthians 14

So lets talk a little about speaking in tongues.

There is two ways to interpret this word "Tongues". It can either be another language, or glossolalia. That's right glossolalia (Yeah I learned that word today too). Glossolalia would be speaking a different language that no one understood. Speaking your own mumblings and words that only you could understand.

On the day of Pentecost Jesus' disciples spoke in tongues, but they were speaking other languages that the people understood. The people were in awe because they knew those people weren't from where they were. It would kind of be like me speaking English to myself but someone hearing Spanish. This was necessary because well...there weren't any Christians that knew other languages yet. There was no Bible either so it couldn't be translated yet. This was necessary for the spread of the gospel. This speaking in other languages continued in the early church (Including Corinth obviously). After the first 20 years or so, speaking in tongues was pretty much obsolete. So people revived it in the form of utterances and a language that is only intelligible to them (glossolalia). This happened around 1905-1908.

Out of this grew the Pentecostal and Charismatic movements. Some churches continue to practice this glossolalia in service. If you ever experience going to a church that includes this in the service, it doesn't tend to be how Paul outlines it in the end of chapter 14. People tend to yell out, start singing, speak to themselves, and so forth.

If you want to read and learn more about this go to this link: http://markmoore.org/resources/essays/tongues.html
The author of this is Mark Moore, and he is a much smarter man that I am. His essay includes everything form history to linguistic samples of people talking in tongues.