I know God is real, Tom, and I know the Baptism of His Holy Spirit is real and I don't go just by feeling good......Can I give you Scriptures to prove my point? I am not sure as I can prove it to myself, but proving it to others is difficult unless they experience the Holy Ghost Baptism themselves! A Christian will show the fruits of God's Spirit as well as the gifts....some or all! This is by the calling of God to serve Him in the capacity that He wants us to do for our good and for His purpose! (Romans: 8 (2

)
An unbeliever or an unsaved person will have some fruits of the Spirit but really does not have them through God's Holy Spirit until saved from all their sins, as there is some good and some bad in all of us! That is why we must grow in the faith and knowledge of God's Word, daily, after we receive His saving grace and do His Will by obedience to and faith in Christ Jesus!
I will try my best to study the Scriptures you have asked for info on the subject of the Spiritual gifts, especially of the the one of Speaking in tongues to be truly saved! I still believe this is just one of the gifts and when we have this gift it is a sign to unbelievers that God is real and for the Christians to receive comfort and peace in their trials by the edification of the Church Body which we all go through from time to time. Faith and works go together and we prove who we are in Christ by using them for the glory and praise of God, our Heavenly Father!
People can believe or not believe in the power of God's Holy Spirit but He does give us power to endure and overcome and I am not of a cult! There are so many different beliefs even in the same faiths of Baptists, Pentecostals, Catholics and so on.....that is why there are so many different churches....But the main Church we should all belong to is the Body of Christ to Whom we belong when we accept Him as Savior and Lord of our lives by believing faith in Jesus and by the leading and guiding of the Holy Spirit of God! We can only overcome through Him and have everlasting life with Jesus forever more!
Does this include that we must speak in tongues.....I don't think so, but that is my opinion, for there are many gifts and God gives one or all of them to whoever he wants to serve Him faithfully in spreading the Gospel of Jesus Christ to the whole world! I have several gifts including Speaking in Tongues, but that doesn't mean I am greater than anyone else who is a true Christian serving God! We can only serve in what we know at the time we are saved and then we must grow in truth and knowledge to have godly wisdom for a better and blessed life! That is why we must ask, seek and search and study the Bible, diligently, to show ourselves approved of God as a workmen that needs not be ashamed of the Gospel! The more we draw nearer to Him, the more He will draw nearer to us! I love it when my Lord and Savior elates me up higher into His Spiritual realm as I pray, seek and serve Him, gladly! Do I know everything? OH NO! I am learning more and more just like anyone else who wants to be nearer to God and serve Him more faithfully by our believing faith in Jesus Christ!
I will end here and study when I can see better....I have a sinus headache today....(satan doesn't want me to study or pray) and my eyes are very weak......But I will....just give me a couple of days to pray, seek the will of my Father and study and I will try to do my best to get back with you! Actually, I really have trouble understanding what you have posted and really want to understand from the Scriptures to prove your point as you gather with others in studying and discussing the Bible! Sometimes, just have to take some teachings by faith or keep asking God until He gives us the answers we are seeking!
May God Bless! Amen!

Ma Betty