'Intended' in the Bible

Food is for the stomach and the stomach for food, but God will do away with both of them. The body is not intended for sexual immorality, but for the Lord, and the Lord is for the body [to save, sanctify, and raise it again because of the sacrifice of the cross].

It follows that speaking in other languages is intended as a sign, not for believers but for unbelievers. But prophecy is not for unbelievers but for believers.