7 How then, brethren, because he that is baptized in Christ, and believes on Him, does not speak now in the tongues of all nations, are we not to believe that he has received the Holy Ghost? God forbid that our heart should be tempted by this faithlessness. Certain we are that every man receives: but only as much as the vessel of faith that he shall bring to the fountain can contain, so much does He fill of it. Since, therefore, the Holy Ghost is even now received by men, some one may say, Why is it that no man speaks in the tongues of all nations?
Because the Church itself now speaks in the tongues of all nations. Before, the Church was in one nation, where it spoke in the tongues of all. By speaking then in the tongues of all, it signified what was to come to pass; that by growing among the nations, it would speak in the tongues of all. Whoso is not in this Church, does not now receive the Holy Ghost. For, being cut off and divided from the unity of the members, which unity speaks in the tongues of all, let him declare for himself; he has it not.
For if he has it, let him give the sign which was given then. What do we mean by saying, Let him give the sign which was then given? Let him speak in all tongues. He answers me: How then, do you speak in all tongues? Clearly I do; for every tongue is mine, namely, of the body of which I am a member. The Church, spread among the nations, speaks in all tongues; the Church is the body of Christ, in this body you are a member: therefore, since you are a member of that body which speaks with all tongues, believe that thou too speakest with all tongues. For the unity of the members is of one mind by charity; and that unity speaks as one man then spoke.
Source: Tractates on the Gospel of John (New Advent)