1 Cor 1:7 So that ye come behind in no gift; waiting for the coming of our Lord Jesus Christ: 8 Who shall also confirm you unto the end, that ye may be blameless in the day of our Lord Jesus Christ. 9 God is faithful, by whom ye were called unto the fellowship of his Son Jesus Christ our Lord. 10 Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you; but that ye be perfectly joined together in the same mind and in the same judgment. 11 For it hath been declared unto me of you, my brethren, by them which are of the house of Chloe, that there are contentions among you.
The Corinthian church devolved into a mess, and therefore Paul had to write them to set things straight. They had divided loyalties about leadership. They were suing each other in court. There was rampant sexual sin within the church and the list goes on. Misuse of spiritual gifts were also a problem in the church at Corinth. He did not write them to discourage or divide, but to tell them the truth and set things in order so that the church could be the lighthouse it needed to be. After all, he started that church in the face of much personal persecution and peril. He owed it to them to tell the truth and they owed it to him to read and head.
Members were parroting the pagan religion of the region by ecstatically babbling on in unintelligible languages. Paul was writing to explain spiritual gifts and to instruct them in their practical use in the body. See chapters 12-14. He let them know right off here in chapter one that the true spiritual gifts were real and from God, and if they were from God, there was no reason for division or blame. He would go on to explain that tongues were foreign languages, and if used in church were to be for the purpose of winning the lost that were present who spoke those languages, notably Jews. If they were to speak these languages in church, they were to interpret what was being said, and that only men were to give the gospel in the foreign language.
I have just addressed a complex issue in a nutshell form, but suffice it to say that God has gifted His church and his children for the purpose of unity and functionality, not to divide. If God were to enable a person to speak in a real foreign language to give the gospel to the lost and all the guidelines were followed, then glory to God. However, the use of modern "speaking in unknown tongues" is divisive and of the devil and is not a practice to be employed by Bible believing Christians.