Why is this here? I think that there must have been unloving, disorderly, and divisive use of tongues in this church. That's all he seems to be addressing. . . so far.
Though "tongues" in Acts clearly describes real human language spoken somewhere in the world, he leaves the door open, at least, that he may be talking about something else here. He seems to be describing an ecstatic utterance that you will enjoy, but other people won't understand.
In the church he sees little or no place for tongues because they do not build others up. If other people don't understand our worship, what good is it to them. This has many applications. You must seek understanding if other people are involved.
If you do not engage the mind and the understanding, you will not be able to sustain the Christian faith. It requires knowledge and understanding.