To pray in tongues, you need to realize that speaking with an unknown tongue is the voice of your heart.
When you receive Jesus Christ as Lord of your life, spiritual death is taken from you and you become a new creature in Christ. And without the Holy Spirit, your new birth wouldnít be possible. But even after you become a new creation, Godís desire and plan is that you receive the Baptism in the Holy Spirit.
Your baptism in the Holy Spirit is received by faith. Jesus said in Luke 11:13, If ye then, being evil, know how to give good gifts unto your children: how much more shall your heavenly Father give the Holy Spirit to them that ask him? When you ask in faith, the Holy Spirit comes to live in you. And when you are filled with the Holy Spirit, as in the book of Acts, you speak in tongues.
Speaking in tongues is simply speaking in a language that only God understands, even you wonít understand it. This happens as the Holy Spirit prays through you about things you may not know about or may not know how to pray about (Romans 8:26).
The Holy Spirit was sent to be our Helper. So when you pray in tongues, what actually happens is that the Holy Spirit searches your heart and prays through you the perfect will of God (Romans 8:26-27). You actually utter the secret truths and hidden things which are not obvious to the understanding of your mind (1 Corinthians 14:2, The Amplified Bible).
To pray in tongues, you need to realize that speaking with an unknown tongue is the voice of your heart. Speaking in a known tongue is the voice of the human mind (unless one of the vocal gifts of the nine gifts of the Spirit is in operation). The Holy Spirit of God will give you utterance, the same as your mind gives you thoughts to speak (Acts 2:4).
To speak in tongues, you must operate with the Holy Spirit. The Apostle Paul said in 1 Corinthians 14:14, For if I pray in an [unknown] tongue, my spirit [by the Holy Spirit within me] prays, but my mind is unproductive (The Amplified Bible).
Notice that it was Paul who did the speaking. Ask the Holy Spirit to take charge of your tongue, then yield your tongue to His use. You cannot speak in your own language and tongues at the same time, just as you cannot speak with English and French at the same time. When your voice and tongue begin forming syllables around the expression that your heart desires to release, you will also speak in tongues. It will be your tongue, your breath, your vocal cords and you will be actively forming words. You will supply the sounds, but the Holy Spirit will supply the words, words unknown to you. It may seem awkward to you at first, but continue. Like a child learning to speak, you will grow.
Finally, as you seek the Baptism in the Holy Spirit, you need not wait to get a word from God about it, you already have His Word, nor do you need to wait around for the Spirit. The Spirit of God entered His ministry on the Day of Pentecost and He has been here ever since. He has never left!
Furthermore, you need not be concerned over being deceived and ending up with something that is from the devil. When you ask your heavenly Father for one of His promises, as the Baptism in the Holy Spirit, you can be confident the gift given is from God, not Satan.
Remember, Luke 11:13 says, how much more shall your heavenly Father give the Holy Spirit to them that ask him? So if you want to receive your baptism in the Holy Spirit, ask Him now.
Heavenly Father, I am a believer. I am Your child and You are my Father. Jesus is my Lord. I believe with all my heart that Your Word is true.
Your Word says if I will ask, I will receive the Holy Spirit. So in the Name of Jesus Christ, my Lord, I am asking You to fill me to overflowing with Your precious Holy Spirit. Jesus, baptize me in the Holy Spirit.
Because of Your Word, I believe that I now receive and I thank You for it. I believe the Holy Spirit is within me and, by faith, I accept it.
Now, Holy Spirit, rise up within me as I praise God. I fully expect to speak with other tongues, as You give me the utterance.
Now begin giving sound to the expressions in your heart. Speak and hear the Holy Spirit speaking through you.
Rejoice! You've just been baptized in the Holy Spirit! You've been endued with power, hallelujah!
Scripture References: Luke 11:10-13; Acts 2:4; Jude 20; 1 Corinthians 14:4