Jesus made us aware that when we go to preach to all nations, and they believe, we should baptize them to be saved (Mark 16:16). Once a person is saved, certain signs will follow him/her as evidence of the new life in Christ Jesus. One of those signs is speaking in a new tongue or language (Mark 16:17). What is this new tongue?

Further, as the Apostle Paul indicated in 1 Corinthians 13, even if he speaks with the tongues of men and of angels and has no charity, he is useless (1 Corinthians 13:1). This suggests that there is a language angels speak and it is not a known language amongst men.

God, who created all things [including human language], also has a language He speaks.

This is the language of the kingdom of heaven. Now, why should tongues [or languages] be important to Christians and also the Christian faith?

• Language determines a people’s identity: Whatever language I speak, when I go anywhere in the world and I meet someone who speaks the same language as mine, I will quickly identify with the person as a brother, friend, or countryman. The same applies to the kingdom of God. The one who speaks in tongues identifies with God Almighty.
• Language Engenders Unity: In Shinar, the people of the east were able to unite for one purpose—to build the tower of Babel. This was because they were all speaking one language (Genesis 11:1). The only way the project was stopped midway was because God confounded their language (Genesis 11:6-7). As Christians speak in God’s tongue, we unite as one people before heaven, and every corporate prayer in tongues projects our unity before the throne of God.
• Language Promotes Effective Communication: If you want to speak to a man’s heart, speak to him in his native language. People understand people better when they are communicated to in their native language. Similarly, our relationship with God can be more effective when we communicate more in His language. This is why every Christian must yearn to speak the language of God.

In Scripture, three different kinds of tongues or languages of the Spirit are revealed — other tongues, diverse kinds of tongues, and the unknown tongue. These three are not the same and must be well understood and appreciated.

a.       Other Tongues: On the day of Pentecost, the disciple spoke a new tongue and scripture described that tongue as other tongues (ἕτερος  -  heteros - het'-er-os). Other tongues refer to speaking in a different or another language but of the same class [or tongues of men]. During prayer, some people speak other tongues as the Spirit gives them utterance. Those who had come from other nations to worship in Jerusalem on the day of Pentecost heard the disciples speak in languages of their nations – Cyrene, Rome, Egypt, Libya, Phrygia, Pamphylia, Asia, Cappadocia, etc (Acts 2:8-11).

b.       Diverse Kind of Tongues: This category of tongue is the ability to speak different languages [tongues of men] as and when the need arises, yet the one with the gift hasn’t learnt any of the languages. Diverse kinds of tongues (γένος – genos - ghen'-os) enable the believer to communicate with others in their language, especially those who do not believe the gospel, as a sign of God’s power. This particular tongue is a manifestation gift of the Spirit and it is supernatural.

c.       Unknown Tongues: Apostle Paul wrote to the Corinthian church about tongues and speaking in tongues. He mentioned that there is a tongue or language called the unknown tongue (ἄγνωστος - agnōstos - ag'-noce-tos), which when a believer speaks, only God can understand (1 Corinthians 14:1-2). The God who created the language of the Germans, the Arabs, the Asians, the African, etc. has a language He shares with His people. It is a language that is in its class and more light is thrown on it.