Sorry, you'r both right. The Bible is NEVER wrong!
Sorry but there's only one truth; Gifts are for the common good (full explanation in 1 Cor 12- the body of Christ) but remember Paul is writing a letter to correct a wrong that was happening. If gifts are for the common good then the wrong that was happening was self edification. They can't be both correct and it is wrong for someone to carefully pick a list of the wrong things and teach them as acceptable.
The summary of 1 Cor 14 is this:
1 Cor 14: 9So it is with you. Unless you speak intelligible words with your tongue, how will anyone know what you are saying? You will just be speaking into the air. 10Undoubtedly there are all sorts of languages in the world, yet none of them is without meaning.