One must check with the scriptures to see if what they are taught is true according to the scriptures.
Tongues were for 1. a sign, 2. to the Jews, 3. during the laying of the foundation, 4. it was a prophecy fulfilled, 5. it was a testimony from God that what the apostles spoke was from Him, along with all the other miracles the apostles could do, 6. the tongue speaker spoke supernaturally so that those with foreign languages heard the message in their language supernaturally, 7. the tongue speaker spoke mysteries, teachings about the gospel.
The sign was given to the Jews during the laying of the foundation the prophecy was fulfilled and God already testified to it, no one is using tongues to give those the message of God in other foreign languages, the mystery has been given, we have the scriptures in the Bible and it is finished.