I believe that the Holy Spirit's gift of Tongues was primarily the gift to speak and everyone else, regardless of their own native language, hears the speaker in their own native tongue even though the Speaker may not even know or speak that language. I believe it was for the edification and glorification of God and was primarily used in early days of Christianity.
I have been in Churches where people have started speaking a language that I don't think is any native language but are more those unidentifiable utterances. When I hear such during a Church Service or during Prayer it is difficult but I try not to judge it one way or another. It is my understanding that if one speaks in the unknown tongues there would be one there with the gift to interpret what is said but it is difficult to reconcile at times. But if it's not for me it's not for me and maybe there is someone there that it is for so I try not to judge either way.
1 Corinthians 14:21-25 NIrV
In the law it is written, “With unfamiliar languages and through the lips of outsiders I will speak to these people. But even then they will not listen to me.” (Isaiah28:11,12 ) That is what the Lord says.  So speaking in other languages is a sign for those who don’t believe. It is not a sign for those who do believe. But prophecy is not for those who don’t believe. It is for those who believe.  Suppose the whole church comes together and everyone speaks in other languages. And suppose visitors or unbelievers come in. Won’t they say you are out of your minds?  But suppose unbelievers or visitors come in while everyone is prophesying. Then they will feel guilty about their sin. They will be judged by all.  The secrets of their hearts will be brought out into the open. They will fall down and worship God. They will exclaim, “God is really here among you!”
The thing I take from the gift of Tongues is more it is for God's Use and if there is a Use or reason then God should be honored and worshiped but if it is for God then it should be evident and for one's edification.
I do believe that God bestows His Holy Spirit within each true Believer and that along with God's Holy Spirit comes different fruits or benefits and those are listed in Galatians 5:22- and those are for the benefit or ministry to the specific Christian.
Galatians 5:22-26 NIrV
But the fruit the Holy Spirit produces is love, joy and peace. It is being patient, kind and good. It is being faithful  and gentle and having control of oneself. There is no law against things of that kind.  Those who belong to Christ Jesus have nailed their sinful desires to his cross. They don’t want these things anymore.  Since we live by the Spirit, let us keep in step with the Spirit.  Let us not become proud. Let us not make each other angry. Let us not want what belongs to others.
Of those fruits/benefits I don't see tongues listed but that is not to say God cannot or will not bestow special gifts or tools upon a believer at a specific time for a specific purpose. Again the way I look at it is it was a purpose and evidence of God's work in the early Church but for the modern Church I try not to judge when I hear someone "speaking in tongues" or the "unknown language".