It’s tough to discern real speaking in tongues and gibberish. You want to be careful not to oppose something from God. On the other hand, the Catechism teaches that charisms like speaking in tongues are for the benefit of the Church. If you can’t understand what is said, then what benefit do we gain?
The Catechism also teaches that charisms are to be referred and submitted to the Church for discernment and testing so that they can work “for the common good”. When has this happened?
Charismatics believe that anyone can speak in tongues at the drop of a hat. All you have to do is lay hands on them and out it comes. This would be nice but gifts of the Holy Spirit are rare (like healing) and not a common phenomenon. I even had a Charismatic tell me that she has to practice speaking in tongues. If that were true, then it seems like it comes from the person and not the Holy Spirit. How do you practice a gift from God?
The Church has taken a hands-off approach to the Charismatic Movement and has not lived up to their pastorial duties to investigate and make sure that we can all benefit from it if it is truly real. In my opinion, I believe that the Church doesn’t want to interfer in something (real or unreal) that brings people closer to God. This is the same approach that they take on some borderline superstitous practices from sacrementals (like the brown scapular).
One more thing. Charismatics that I talk to speak about a baptism of the Holy Spirit that is separate from the sacraments. Some how we don’t get the full gifts of the Holy Spirit through baptism and confirmation. This seems to be a common belief of Charismatics but it is clearly against Church teaching.