Paul’s main point in these 25 verses is to stop the Corinthians from filling their church meetings with publicly given tongues that are not then interpreted, but rather to encourage them to eagerly desire the intelligible gifts of the Spirit, such as prophecy, so that everyone can understand what’s being said.

Therefore, he argues, a publicly given tongue should be interpreted, so that everyone can understand the essence of what was said, whether by someone else or the tongue giver themselves, if no one else interprets it.