(1) Correctly: TONGUES = SPOKEN LANGUAGES, ie, sounds made by the mouth TO CONVEY AN INTELLIGIBLE MESSAGE.
(2) Incorrectly: TONGUES = SPOKEN GIBBERISH, ie, sounds made by the mouth WHICH CANNOT BE UNDERSTOOD BY ANYONE.
(1) The missionaries quickly learned the native tongues of the indiginous peoples and preached the gospel to them.
(2) Molly babbled some gibberish during the service, and explained that I couldn't understand it because it was the "tongues of angels". I said that the Greek and Hebrew phrases for "tongues of angels" mean "languages of messengers" and that the words for "language" and "messenger" (both indicate coveying a MESSAGE) can only support the saying as being meant to be UNDERSTOOD.