Great question, Charlene!
Speaking in tongues has never been infallibly defined by the Church; however we do have the Catholic Charismatic Renewal movement, where the gifts of the Holy Spirit - including tongues - are exercised, and this movement has papal approval.
For those who are not familiar with this gift, it is one of the gifts of the Holy Spirit, given to us on Pentecost, as defined in 1 Corinthians 13:1. The gift of tongues is specifically addressed in 1 Corinthians 14.
The gift can manifest in either an "angelic" language or in an earthly language not known by the speaker. This gift was given by the Spirit to the Church for the edification of the Body of Christ and for glorifying the Lord.
There are several different kinds of tongues: 1) a private prayer language; 2) a language used in prophecy which requires interpretation, and; 3) a missionary tongue which is the speaking of otherwise unknown languages in order to spread the gospel.
The Catechism describes the gift of tongues as a special grace or "charism"(a Greek word meaning "favor"). "Whatever their character - sometimes it is extraordinary, such as the gift of miracles or of tongues - charisms are oriented toward sanctifying grace and are intended for the common good of the Church. They are at the service of charity which builds up the Church" (No. 2003).
That said, there is some division within the Christian community about tongues with some (including a few of our Early Church Fathers) who believe this gift was meant for first century Christianity and not today.
For instance, St. Augustine wrote "Why then is no one speaking in the tongues of all the nations just as he spoke who at the time was being filled with the Holy Spirit. Why? Because this was a sign that has been satisfied."
Division is also occurring because of the many abuses of tongues in Christian circles, such as in cases where the faithful are being told they cannot be saved without this gift, or that this gift is a sign that they have been truly "baptized in the Spirit."
Speaking in tongues is not necessary for salvation, or for anything else for that matter. As St. Paul teaches in 1 Cor 13:1-2, 13 "If I speak with the tongues of men and of angels, but do not have love, I have become a noisy gong or a clanging cymbal. 2 And if I have the gift of prophecy, and know all mysteries and all knowledge; and if I have all faith, so as to remove mountains, but do not have love, I am nothing....13 But now abide faith, hope, love, these three; but the greatest of these is love."
On a side note, I came across this interesting article in The New York Times which reports on research done by neuroscientists at the University of Pennsylvania who took brain images of five women while they were speaking in tongues to determine their brain activity. What they found is that their frontal lobes — the thinking, willful part of the brain through which people control what they do — were relatively quiet, as were their language centers.
"The regions involved in maintaining self-consciousness were active. The women were not in blind trances, and it was unclear which region was driving the behavior," the article states.
Researchers used imaging techniques to track the blood flow in the brain of the women when they were singing a gospel song and again while praying in tongues, then compared the two. The patterns created by blood-flow peaks and valleys was unique to those praying in tongues.
One of the co-authors of the study, Donna Morgan, a born-again Christian who also served as one of the research subjects, has the gift of tongues and describes what it feels like to pray in this way.
“You’re aware of your surroundings. You’re not really out of control. But you have no control over what’s happening. You’re just flowing. You’re in a realm of peace and comfort, and it’s a fantastic feeling.”
This could explain why studies suggest that people who speak in tongues rarely suffer from mental problems.
"A recent study of nearly 1,000 evangelical Christians in England found that those who engaged in the practice were more emotionally stable than those who did not."
The gift of tongues is just that - a gift - and one that is given only as a means of serving God and the Church and should never be presented as a prerequisite for anything.
We pray that God will bless you abundantly during this precious journey into our beloved Church!