Perhaps you are wondering about speaking in tongues. That really means an "unknown" language. On the day of the Pentecost the Disciples were preaching and teaching in languages unknown to them, but the hearers heard in their own tongues. Acts 2:6 ­ "Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language." 

Chapter 14 of I Cor. lists speaking in an unknown tongue (even with an interpreter) as the least of the gifts. 

Because we Christians have the Holy Spirit dwelling in us, we are to have the "fruit of the Spirit." Gal. 5:22-23: "But the fruit of the Spirit is love, joy, peace, long suffering, gentleness, goodness, faith, meekness, temperance, against such there is no law."

"These fruits are like clusters of grapes. The first cluster of the fruit, Love, Joy and Peace, has a primary Godward relationship, with outward results that others can see. Thus we speak of the love of God, joy of the Lord, and the peace of God. The second cluster­patience, kindness and goodness has to do with the kind of Christian we are, in our outward relationship to others. If we are unkind, and rude, short tempered, we lack the second cluster of fruit. The third cluster of spiritual fruit ­ faith, meekness, temperance (self-control) has to do with the inward man. Faith means to be faithful to our Christian commitments!" B.G. 

We as Christians can grieve the Holy Spirit, and we do that when our lives are not God honoring. Eph. 4:30 ­ "And grieve not the Holy Spirit of God, whereby ye are sealed unto the day of redemption."

Anything untrue or deceitful that we do ­ doubt, worry, unloving; such characteristics grieve Him. Anything that is unclean, defiling or degrading in our lives grieves the Holy Spirit within us. 

The Holy Spirit is likened to a dove ­ Matt. 3:16 ­ "And Jesus, when He was baptized, went up straightway out of the water: and lo the Heavens were opened unto Him and He saw the Spirit of God descending like a dove, and lighting upon Him."

A dove is a bird that is quickly disturbed; the slightest wrong movement, and he is gone. Oh! How careful we should be not to grieve the Holy Spirit! 

"We are also told not to quench the Holy Spirit. I Thess. 5:19 ­ "Quench not the Spirit..." The word 'grieve' suggests the sense of hurting or making the Holy Spirit sorrowful. The word 'quench' means to 'put out' or 'put a damper on'." B.G. 

By lack of prayer and Bible study, sinful deeds, etc., we put out the fire. You have often heard the expression, "he is on fire for the Lord". When we quench the Holy Spirit, we are no longer "on fire for the Lord".