There Is A Huge Difference Between The Gift On Tongues And Interpretation And The Gift Of The Unknown Tongue

The Holy Spirit
The baptism of the Holy Spirit is real and available to you today.
Speaking in tongues is Biblical.
Liberalism rejects the power of the Holy Spirit

Only if a person is moved upon by the Holy Spirit can they believe and receive salvation.  That is plain in Scripture.  Yet, there is a difference between having the Holy Spirit move upon us so we can believe and being baptized (immersed) in the Holy Spirit and speaking to God and to angels in the unknown tongue.  A Christian doesn't have to speak in tongues, but they get to, and the Bible says that it builds them up.  They don't get saved to speak in tongues, but it's a lot like when you buy shoes--you don't buy a pair of tongues; the tongues just come along with the shoes.  Just as with other gifts of God (healing, prayer, the fruit of the Spirit, etc.) some Christians reject God's free gifts.

In addition to the free gift of the unknown tongue that all receive, there is a gift of tongues by which only some gifted persons may speak in the tongues of men--human tongues.  There is also a gift of interpretation of tongues.  We see this manifest in the twentieth Century church, though not as much as we should see it.  It is a testimony, a miracle, to the unsaved.

The gift of the unknown tongue

1 Corinthians 14:2 For he that speaketh in an [unknown] tongue speaketh not unto men, but unto God: for no man understandeth [him]; howbeit in the spirit he speaketh mysteries. 

1 Corinthians 14:5-6 I would that ye all spake with tongues, but rather that ye prophesied: for greater [is] he that prophesieth than he that speaketh with tongues, except he interpret, that the church may receive edifying.  Now, brethren, if I come unto you speaking with tongues, what shall I profit you, except I shall speak to you either by revelation, or by knowledge, or by prophesying, or by doctrine? 

1 Corinthians 14:14-15 For if I pray in an [unknown] tongue, my spirit prayeth, but my understanding is unfruitful.  What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.

1 Corinthians 14:18-19 I thank my God, I speak with tongues more than ye all:  Yet in the church I had rather speak five words with my understanding, that [by my voice] I might teach others also, than ten thousand words in an [unknown] tongue. 

The Spiritual Gift of Tongues and Interpretation--given only to some according to God's will.

1 Corinthians 14:21-22 In the law it is written, With [men of] other tongues and other lips will I speak unto this people; and yet for all that will they not hear me, saith the Lord.  Wherefore tongues are for a sign, not to them that believe, but to them that believe not: but prophesying [serveth] not for them that believe not, but for them which believe. 
 
1 Corinthians 14:26-28 How is it then, brethren? when ye come together, every one of you hath a psalm, hath a doctrine, hath a tongue, hath a revelation, hath an interpretation. Let all things be done unto edifying.   If any man speak in an [unknown] tongue, [let it be] by two, or at the most [by] three, and [that] by course; and let one interpret.   But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God. 

1 Corinthians 14:39-40 Wherefore, brethren, covet to prophesy, and forbid not to speak with tongues.  Let all things be done decently and in order. 

1Co 12:10 and to another workings of miracles; and to another prophecy; and to another discernings of spirits; to another divers kinds of tongues; and to another the interpretation of tongues:

2 Corinthians 3:6 Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.