Objection 1. It seems that those who received the gift of tongues did not speak in every language. For that which is granted to certain persons by the divine power is the best of its kind: thus our Lord turned the water into good wine, as stated in John 2:10. Now those who had the gift of tongues spoke better in their own language; since a gloss on Hebrews 1, says that "it is not surprising that the epistle to the Hebrews is more graceful in style than the other epistles, since it is natural for a man to have more command over his own than over a strange language. For the Apostle wrote the other epistles in a foreign, namely the Greek, idiom; whereas he wrote this in the Hebrew tongue." Therefore the apostles did not receive the knowledge of all languages by a gratuitous grace.
Objection 2. Further, nature does not employ many means where one is sufficient; and much less does God Whose work is more orderly than nature's. Now God could make His disciples to be understood by all, while speaking one tongue: hence a gloss on Acts 2:6, "Every man heard them speak in his own tongue," says that "they spoke in every tongue, or speaking in their own, namely the Hebrew language, were understood by all, as though they spoke the language proper to each." Therefore it would seem that they had not the knowledge to speak in all languages.
Objection 3. Further, all graces flow from Christ to His body, which is the Church, according to John 1:16, "Of His fullness we all have received." Now we do not read that Christ spoke more than one language, nor does each one of the faithful now speak save in one tongue. Therefore it would seem that Christ's disciples did not receive the grace to the extent of speaking in all languages.
On the contrary, It is written (Acts 2:4) that "they were all filled with the Holy Ghost, and they began to speak with divers tongues, according as the Holy Ghost gave them to speak"; on which passage a gloss of Gregory [Hom. xxx in Ev.] says that "the Holy Ghost appeared over the disciples under the form of fiery tongues, and gave them the knowledge of all tongues."
I answer that, Christ's first disciples were chosen by Him in order that they might disperse throughout the whole world, and preach His faith everywhere, according to Matthew 28:19, "Going... teach ye all nations." Now it was not fitting that they who were being sent to teach others should need to be taught by others, either as to how they should speak to other people, or as to how they were to understand those who spoke to them; and all the more seeing that those who were being sent were of one nation, that of Judea, according to Isaiah 27:6, "When they shall rush out from Jacob [Vulgate: 'When they shall rush in unto Jacob,' etc.]... they shall fill the face of the world with seed." Moreover those who were being sent were poor and powerless; nor at the outset could they have easily found someone to interpret their words faithfully to others, or to explain what others said to them, especially as they were sent to unbelievers. Consequently it was necessary, in this respect, that God should provide them with the gift of tongues; in order that, as the diversity of tongues was brought upon the nations when they fell away to idolatry, according to Genesis 11, so when the nations were to be recalled to the worship of one God a remedy to this diversity might be applied by the gift of tongues.
Reply to Objection 1. As it is written (1 Corinthians 12:7), "the manifestation of the Spirit is given to every man unto profit"; and consequently both Paul and the other apostles were divinely instructed in the languages of all nations sufficiently for the requirements of the teaching of the faith. But as regards the grace and elegance of style which human art adds to a language, the Apostle was instructed in his own, but not in a foreign tongue. Even so they were sufficiently instructed in wisdom and scientific knowledge, as required for teaching the faith, but not as to all things known by acquired science, for instance the conclusions of arithmetic and geometry.
Reply to Objection 2. Although either was possible, namely that, while speaking in one tongue they should be understood by all, or that they should speak in all tongues, it was more fitting that they should speak in all tongues, because this pertained to the perfection of their knowledge, whereby they were able not only to speak, but also to understand what was said by others. Whereas if their one language were intelligible to all, this would either have been due to the knowledge of those who understood their speech, or it would have amounted to an illusion, since a man's words would have had a different sound in another's ears, from that with which they were uttered. Hence a gloss says on Acts 2:6 that "it was a greater miracle that they should speak all kinds of tongues"; and Paul says (1 Corinthians 14:18): "I thank my God I speak with all your tongues."
Reply to Objection 3. Christ in His own person purposed preaching to only one nation, namely the Jews. Consequently, although without any doubt He possessed most perfectly the knowledge of all languages, there was no need for Him to speak in every tongue. And therefore, as Augustine says (Tract. xxxii in Joan.), "whereas even now the Holy Ghost is received, yet no one speaks in the tongues of all nations, because the Church herself already speaks the languages of all nations: since whoever is not in the Church, receives not the Holy Ghost."
Source: Summa Theologica (New Advent)