There is, for instance, a certain number of different languages in the world, and not one of them fails to convey meaning.
If, however, I do not happen to know the language, I shall be a foreigner to those who speak it, and they will be foreigners to me.
And so with you; unless, in using the gift of 'tongues,' you utter intelligible words, how can what you say be understood? You will be speaking to the winds!