Tongues are DISTINCTIVE of the New Covenant Creation. They are only mentioned by Jesus Christ after He rose from the dead, when He introduced them as a normal part of the New Life and restored dominion in Christ.
Having said, 'ALL AUTHORITY IS GIVEN TO ME' ( Matthew 28:18),
Jesus said in Mark 16:15-18:'Go into all the world and preach the gospel to every creature .... and these signs will follow those who believe in My Name (In My name) they will cast out demons (exercise spiritual dominion over satan) they will speak with new tongues (they will exercise the dominion of the spirit over the flesh and mind by being able to speak from their spirit) they will take up serpents and if they drink anything deadly, it will by no means hurt them they will lay hands on the sick, and they will recover (dominion over natural dangers, especially sickness).'
Notice that restored spiritual dominion including the ability to speak in other tongues (unknown languages) is the privilege of all who believe in His NAME - that is all Christians.
This New Creation Commission is parallel to the original Commission given to Adam at Creation. He gave man DOMINION and told him to MULTIPLY and FILL the earth. Likewise after His resurrection Christ gave New-Creation Man DOMINION (the authority in His Name) and the command to MULTIPLY and FILL the earth through spreading the seed of the Word. In this context the gift of tongues is part of our restored spiritual dominion. Through it our spirit can assert dominion over the mind and flesh and pray God's perfect will into our lives.
Through the New Birth we became a New Creation (2Cor5:17), made the Righteousness of God in our spirits (2Cor 5:21). Adam was a 'living soul' who then sinned and came under the power of the flesh but we are now made life-giving spirits (1Cor 15:45). We still have our flesh and sin (a sin-nature) in our flesh, but our spirits are no longer under the dominion of the flesh (Rom 8:1-10).
YOU ARE A SPIRIT - YOU HAVE a MIND and you live in a BODY.
From the Fall we have been mind and body-ruled but in the New-Birth, God has recreated our spirit, freeing it from the dominion of sin in the flesh (Romans 6) so that now we can live, speak and walk out of our spirit not our flesh. There is a new centre of personhood. Our good-works (God's plan for our life) are programmed into our reborn spirit (Eph 2:10) and as we walk in the spirit (energised by the Holy Spirit and under the Lordship of Jesus) they are manifested in our lives. When we pray in tongues we speak out these plans and purposes: 'he who speaks in a tongue does not speak to men but to God, for no one understands him; however, in the spirit he speaks mysteries (the secrets of your life).' (1Cor 14:2).
Acts 2:4: 'They were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit gave them utterance.'
This was the first and blueprint experience of speaking in tongues, and it describes clearly how it works. Notice that they ALL spoke - this same pattern continued throughout Acts. Thus today, it is available to all believers.
Peter declared that the Promise of the Holy-Spirit, poured out from heaven by Jesus, includes tongues: 'the promise of the Holy Spirit, He poured out this which you now see and hear' (v32).
Then he said that this promise was for all believers: 'you shall receive the gift of the Holy Spirit. For the promise is to you and to your children, and to all who are afar off, as many as the Lord our God will call.' It has already been poured out and given to the Church. So, in Acts they never prayed God would GIVE the Spirit, just for them to RECEIVE. Likewise we teach and pray for believers to receive what God has already given.
'He who speaks in a tongue edifies himself (charges himself up like a battery)' (1Cor 14:4). It is good for your spiritual life, so Paul adds:
'I wish you all spoke with tongues' (this is the 4th witness that God's will is for all believers to speak in tongues).
'I thank my God I speak with tongues more than you all' (v18).
'Let him who speaks in a tongue pray that he may interpret. For if I pray in a tongue, my spirit prays, but my understanding is unfruitful. What is then? I will pray with the spirit, and I will also pray with the understanding. I will sing with the spirit, and I will also sing with the understanding' (v13-15).
When you pray in tongues your mind quietens down and becomes receptive to the thoughts that the Spirit is expressing. You begin to pick up impressions and interpretation of what you are praying about. In this way you hook up with God's wisdom and creative ideas flow into your consciousness of what you should do. Praying in tongues is under the control of your will and should be part of our prayer-life, especially useful when we don't know how to pray, or don't know God's will in a situation (Rom 8:26-27).
When you pray in tongues your spirit prays. You choose to give your spirit control of your tongue and this way it gets dominance over your life (see James 3). You spirit speaks out the words of the Holy Spirit. Your spirit wants to express God's will and God's praises but your mind does not want to yield control of the tongue. You must get the revelation from Word that you are a spirit indwelt and yielded to the Holy Spirit and that your spirit wants to express itself. So you yield your tongue to the words of the spirit and as a result God's will gets established in your natural life.
So by tongues you are:
1. Praising God and praying out the will of God for your life.
2. You are establishing the dominance of your spirit over your flesh.
How can the spirit do this? - through the tongue - that's how we are made.
For those who speak in tongues use the gift God has given. Pray out God's will for your life.
For those who don't - step out in faith, realise you are a SPIRIT, with the HOLY- SPIRIT within and ask God to fill you with the Holy-Spirit. HE IS SPEAKING. By faith hook up and start moving your mouth, making a sound, trusting Him to give you the next words. It is a cooperation of faith, you have to continually choose to yield control of the tongue to your spirit and trust the Holy-Spirit to provide the words.