First of all, "tongue" is an archaic English word used during Elisabeth I and Shakespeare's time to mean "language". So basically, these two words are the same, interchangeable. But, the King James Version of the Bible was translated around this time and the word tongue was used instead of language. Today most saints of YAHUSHUA use the word "tongues" when speaking on this gift of the RUACH HaKODESH.
Here's my definition of tongues, as used in the Bible:
Tongues are utterances, by supernatural means, in a language either earthly or heavenly (1 Corinthians 13:1) that the vocalizer has not learned (i.e. has not been naturally trained in). Tongues can be vocalized in three ways:  singing  praying or  speaking/preaching (1 Corinthians 13:14-15).
Tongues will have either one of two sources: the one, true YAHUVEH or demonic spirits. It's either a manifestation of the Holy Spirit (RUACH Ha KODESH) or unholy spirits. Satan seeks to counterfeit everything YAHUVEH does…even the anointing of YAHUVEH (1 John 2:27). Ezekiel 28:14 says that Satan was an ANOINTED cherub before Satan fell in that first war in Heaven. Here is the key, demonic manifestations are accompanied by the works of the sinful nature, whereas, manifestations of the RUACH HaKODESH are accompanied by the fruit of the Spirit! (Go read Matthew 7 and Galatians 5 as soon as possible).
For example, folks that practice voodoo can work themselves in to esoteric trances and start speaking in tongues! (This also explains why Angie Ray labeled her ministry as "Pentecostal / Charismatic"). Mantras work in a similar way and are part of Satan's counterfeit of the genuine tongues. I also knew an unsaved young man who spoke in tongues when he was sick with a high fever. Once I was lying in bed and heard demons using another language. Again, once I was taking the subway and a demonized person yelled at me in tongues and then quickly ran away.
Read Mark 16:17; Matthew 7:16-23 (with 1 Corinthians 13 in mind); James 2.
Lastly, about a year ago I had a related dream. I'll keep it short and simple:
I was in a church building, I got the impression in my spirit that a man wasn't saved and I go over to him to witness. It turns out that he could pray in tongues! Because of that, I ignored the RUACH and did not witness to the man. Then I hear demons mocking, laughing, saying they FOOLED the man and others (including the saints) into believing the man was born again.
The dream doesn't need much interpretation because it's self-explanatory. But clearly, just being able to pray in tongues does NOT even mean you are saved. Also, just because you are in a church building does NOT mean you are in the company of the saints NOR the RUACH HaKODESH. Before this dream, I generally assumed that you were baptized in the RUACH HaKODESH if you could pray in tongues.
Okay that said, don't "throw the baby out with the bath water"! Tongues is very edifying both to individual members of the Church and the Church at large. For the rest of this, whenever I use the term tongues, I'm referring to "Holy Tongues"…namely, tongues that are accompanied by Holiness and other fruit of the HOLY Spirit.
Many people argue about stupid things like the existence of tongues today. (Because that is such a stupid thing to argue about, I will not even address it in detail). Another thing I've heard people argue about are the ideas that you are not saved unless you speak in tongues. Obviously that is NOT true. You are born again the moment you put your trust in YAHUSHUA Ha MASSIACH to save you and you have the witness from the HOLY SPIRIT that you are a child of YAHUVEH.
(Read all of Romans 8 now and pay special attention to verse 16. If you do not feel like you have that witness, do two things. First, remember that we are to walk by faith, not sight or feelings [2 Corinthians 5:7]. And also, I suggest you seek YAHUVEH until you, without a doubt, have that witness and absolute assurance that you KNOW Him).
THE GIFT OF DIVERSE TONGUES AND THE INTERPRETATION THEREOF
The gift of diverse tongues is both Heavenly and Earthly languages (1 Cor 13:1; 14:21-22; Rom 8:26). Both the gift of tongues and the interpretation thereof are for the edification of the church (1 Cor 14:5, 9-23). 1 Cor 14:28 says "If there be no interpreter, let him keep silence in the church; and let him speak to himself, and to YAHUVEH". The gift of tongues can be a sign to unbelievers (1 Cor 14:22), BUT only if the unbeliever understands the language (1 Cor 14: 11; 14:23). For example, read what happened on the day of Pentecost in Acts 2:11.
How does the gift of diverse tongues and their interpretation work?
You need to have at least two saints. One person would speak in tongues and the other person would be given the interpretation in the Spirit.
There are nine "spiritual gifts" listed in first Corinthians twelve:  words of wisdom;  words of knowledge;  extreme faith;  the gift of healing;  the working of miracles  prophecy;  discerning of different spirits;  speaking in different languages; &  the interpretation of unknown languages.
Tongues is similar to the gift of prophecy. It is subject to the speaker. I've often heard it said that "YAHUVEH is a gentleman". He won't shove words down your throat. You are in control of your mouth when you speak or pray in tongues…its not chaotic like demon possession.
1 Corinthians 13:32-33
32And the spirits of the prophets are subject to the prophets.
33For YAHUVEH is not the author of confusion, but of peace, as in all churches of the saints.
I would like to make a further distinction about tongues. There is  the gift of the interpretation of tongues,  the gift of diverse tongues, &  the prayer language. The gift of tongues and the gift of the interpretation of tongues are the last of the 9 spiritual gifts listen in 1 Cor 12. BUT, I believe the prayer language is available to everyone who is born again. A common simile is that the prayer language is like a gift that YAHUVEH has already given you, but you haven't bothered to either open it or even look at the box.
The prayer language is mainly for self edification (1 Cor 14:4). It stirs up the anointing during worship (1 Cor 14:14-16; Ephesians 5:18-20) and aids in prayer (Romans 8:26-27). In 1 Corinthians 14: 19 the Apostle Paul says, "in the church I would rather speak five intelligible words to instruct others than ten thousand words in a tongue". But, it is perfectly acceptable to pray in tongues during ministry because tongues stirs up the anointing to aid in ministry (1 Cor 14:6-8), to bring a revelation, a word of knowledge, a word of wisdom, a prophecy or a word of instruction, (1 Cor 14:6).
As far as I know, the prayer language is usually in a heavenly language (1 Cor 13:1; 14:2; Rom 8:26). Also, the Holy Spirit often tells you what you are praying about or gives you the interpretation of what you are saying (1 Cor 14:13).
Acts 2: 38 Then Peter said unto them, Repent, and be baptized every one of you in the name of YAHUSHUA HA MASHIACH for the remission of sins, and ye shall receive the gift of the Holy Ghost.
39 For the promise is unto you, and to your children, and to all that are afar off, even as many as the LORD our YAHUVEH shall call
The prayer language is an evidence and manifestation of the Baptism in the Holy Spirit. The reason I believe YAHUVEH chose this to be evidence is because of what it says throughout Proverbs and James 3 that no MAN can tame the tongue. Acts 2: 39 talks about the Baptism in the Holy Spirit: " the promise is unto you, and to your children, and to all that are afar off, even as many as the LORD our YAHUVEH shall call".
In the Bible, EVERYTIME someone is Baptized in the Holy Spirit they receive the prayer language. Romans 1 says the gospel goes first to the Jews and then to the Gentiles. In Acts 2:4 you can read about the Jews speaking in new languages as the Spirit gave them utterance. In Acts 8:9-25 you can read about the Samaritans; (tongues is not EXPLICITLY mentioned here, but in verse 18 it says that Simon the Sorcerer*** saw that the RUACH HaKODESH was given and wanted to buy this power. Obviously, unless there was a physical manifestation like in Acts 2, Simon must have seen these believers praying in tongues). In Acts 10: 44-46 you can read about the Gentiles speaking in new tongues.
(***By the way, Simon the Sorcerer was later given over to seducing spirits. Historical sources tell us that he believed he could fly. In an attempt to do so, he jumped off a cliff to his death).
In Acts 9: 17 when Apostle Paul is baptized, the Bible doesn't mention tongues, BUT in 1 Corinthians 14:18, Paul says "I thank YAHUVEH that I speak in tongues more than all of you". When another group is baptized in the Holy Spirit, in Acts 19:6 it says "they spoke in tongues and prophesied". This phrase is repeated all throughout the book of Acts.
I don't make a distinction between being born again and the initial baptism of the Holy Spirit. Some people do, but I don't think it's a big issue. Technically, the first apostles received the Holy Spirit the first time when YAHUSHUA breathed on them in John 20:22 and were then baptized in the Holy Spirit's fire in Acts 2:3-4.
(Remember baptism means to immerse, to bathe, to wash. Once you have been baptized in the HOLY SPIRIT he can refill you or fill you to overflow). Once you have been born again, the power of the HOLY SPIRIT is available to you and it is just a matter of humility and willingness to seek YAHUVEHs Face.
1 Cor 12 says YAHUVEH is the giver of the gifts. The best gift of all is ETERNAL LIFE, to KNOW YAHUVEH (John17:3). And Acts 2: 39 talks about the Baptism in the Holy Spirit (which I believe includes the gift of the prayer language): " the promise is unto you, and to your children, and to all that are afar off, even as many as the LORD our YAHUVEH shall call".
Speaking in Tongues: Medical Study proves it’s the HOLY SPIRIT praying
Glossolalia, otherwise referred to as “speaking in tongues, ” has been around for thousands of years, and references to it can be found in the Old and New Testament.
Research shows that these people are not in control of the usual language centers during this activity,
which is consistent with their description of a lack of intentional control while speaking in tongues. These findings could be interpreted as the subject’s sense of self being taken over by something else.
Biblical references about Speaking in Tongues
1 Corinthians 12:7-11
7 But the manifestation of the Spirit is given to every man to profit withal.
8 For to one is given by the Spirit the word of wisdom; to another the word of
knowledge by the same Spirit;
9 To another faith by the same Spirit; to another the gifts of healing by the
10 To another the working of miracles; to another prophecy; to another
discerning of spirits; to another divers kinds of tongues; to another the
interpretation of tongues:
11 But all these worketh that one and the selfsame Spirit, dividing to every man
severally as he will.
1 Corinthians 13:1
1 Though I speak with the tongues of men and of angels, and have not
charity, I am become as sounding brass, or a tinkling cymbal.
1 Corinthians 14:1-19
1 Follow after charity, and desire spiritual gifts, but rather that ye may
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.
3 But he that prophesieth speaketh unto men to edification, and exhortation, and
4 He that speaketh in an unknown tongue edifieth himself; but he that
prophesieth edifieth the church.
5 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.
6 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?
7 And even things without life giving sound, whether pipe or harp, except they
give a distinction in the sounds, how shall it be known what is piped or harped?
8 For if the trumpet give an uncertain sound, who shall prepare himself to the
9 So likewise ye, except ye utter by the tongue words easy to be understood, how
shall it be known what is spoken? for ye shall speak into the air.
10 There are, it may be, so many kinds of voices in the world, and none of them
is without signification.
11 Therefore if I know not the meaning of the voice, I shall be unto him that
speaketh a barbarian, and he that speaketh shall be a barbarian unto me.
12 Even so ye, forasmuch as ye are zealous of spiritual gifts, seek that ye may
excel to the edifying of the church.
13 Wherefore let him that speaketh in an unknown tongue pray that he may
14 For if I pray in an unknown tongue, my spirit prayeth, but my understanding
15 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
16 Else when thou shalt bless with the spirit, how shall he that occupieth the
room of the unlearned say Amen at thy giving of thanks, seeing he understandeth
not what thou sayest?
17 For thou verily givest thanks well, but the other is not edified.
18 I thank my God, I speak with tongues more than ye all:
19 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
1 Corinthians 14:22-25
22 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.
23 If therefore the whole church be come together into one place, and all speak
with tongues, and there come in those that are unlearned, or unbelievers, will
they not say that ye are mad?
24 But if all prophesy, and there come in one that believeth not, or one
unlearned, he is convinced of all, he is judged of all:
25 And thus are the secrets of his heart made manifest; and so falling down on
his face he will worship God, and report that God is in you of a truth.
26 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.
27 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.
28 But if there be no interpreter, let him keep silence in the church; and let
him speak to himself, and to God.
1 And when the day of Pentecost was fully come, they were all with one
accord in one place.
2 And suddenly there came a sound from heaven as of a rushing mighty wind, and
it filled all the house where they were sitting.
3 And there appeared unto them cloven tongues like as of fire, and it sat upon
each of them.
4 And they were all filled with the Holy Ghost, and began to speak with other
tongues, as the Spirit gave them utterance.
5 And there were dwelling at Jerusalem Jews, devout men, out of every nation
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.
7 And they were all amazed and marvelled, saying one to another, Behold, are not
all these which speak Galilaeans?
8 And how hear we every man in our own tongue, wherein we were born?
9 Parthians, and Medes, and Elamites, and the dwellers in Mesopotamia, and in
Judaea, and Cappadocia, in Pontus, and Asia,
10 Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and
strangers of Rome, Jews and proselytes,
11 Cretes and Arabians, we do hear them speak in our tongues the wonderful works
12 And they were all amazed, and were in doubt, saying one to another, What
13 Others mocking said, These men are full of new wine.
44 While Peter yet spake these words, the Holy Ghost fell on all them which
heard the word.
45 And they of the circumcision which believed were astonished, as many as came
with Peter, because that on the Gentiles also was poured out the gift of the
46 For they heard them speak with tongues, and magnify God. Then answered Peter,
47 Can any man forbid water, that these should not be baptized, which have
received the Holy Ghost as well as we?
6 And when Paul had laid his hands upon them, the Holy Ghost came on them; and
they spake with tongues, and prophesied.
7 And all the men were about twelve.
16 He that believeth and is baptized shall be saved; but he that believeth
not shall be damned.
17 And these signs shall follow them that believe; In my name shall they cast
out devils; they shall speak with new tongues;
18 They shall take up serpents; and if they drink any deadly thing, it shall not
hurt them; they shall lay hands on the sick, and they shall recover.