The supernatural, Spirit granted, gift of tongues is not the same as speaking more than one language.   If you were able to walk into a Chinese restaurant and instantaneously speak fluent Mandarin Chinese and share the Gospel with the workers, that would be a gift of tongues.  This is known as a manifestation of the Spirit as Paul describes in I Corinthians Chapter 12.

1 Cor 12:7-11
7 But the manifestation of the Spirit is given to each one for the profit of all: 8 for to one is given the word of wisdom through the Spirit, to another the word of knowledge through the same Spirit, 9 to another faith by the same Spirit, to another gifts of healings by the same Spirit, 10 to another the working of miracles, to another prophecy, to another discerning of spirits, to another different kinds of tongues, to another the interpretation of tongues. 11 But one and the same Spirit works all these things, distributing to each one individually as He wills.



Another aspect of the gift of tongues is the "speaking in an unknown language".  When this occurs, Paul teaches us, later on, that there should be order and interpretation given.

1 Cor 14:26-28
26 How is it then, brethren? Whenever you come together, each of you has a psalm, has a teaching, has a tongue, has a revelation, has an interpretation. Let all things be done for edification. 27 If anyone speaks in a tongue, let there be two or at the most three, each in turn, and let one interpret. 28 But if there is no interpreter, let him keep silent in church, and let him speak to himself and to God.