I have heard it preached by different denominations that speaking in tongues is paramount to receiving access into Heaven. Many preachers have taught from their pulpits that tongues is this special, private language that only God can understand. 

Before we discuss entrance into heaven, we need to define speaking in tongues. As always, we will look to what the Bible has to say for understanding. The first occurrence of speaking in tongues occurred on the day of Pentecost in Acts 2:1-4

When the day of Pentecost had come, they were all together in one place. 2 Suddenly a sound like a mighty rushing wind came from heaven, and it filled the whole house where they were sitting. 3 There appeared to them tongues as of fire, being distributed and resting on each of them, 4 and they were all filled with the Holy Spirit and began to speak in other tongues, as the Spirit enabled them to speak. 5 Now dwelling in Jerusalem were Jews, devout men, from every nation under heaven. 6 When this sound occurred, the crowd came together and were confounded, because each man heard them speaking in his own language. 7 They were all amazed and marveled, saying to each other, “Are not all these who are speaking Galileans? 8 How is it that we hear, each in our own native language? 9 Parthians, Medes and Elamites, residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, 10 Phrygia and Pamphylia, Egypt and the regions of Libya near Cyrene, and visitors from Rome, both Jews and proselytes, 11 Cretans and Arabs—we hear them speaking in our own languages the mighty works of God.” 12 They were all amazed and perplexed, saying to each other, “What does this mean?”

Throughout the entirety of scripture, the word tongues always means languages. More specifically, known languages. 

Speaking in tongues was the ability to speak in a language the speaker does not know, in order to communicate the gospel to someone who does speak that language. In the multicultural area of Corinth, it seems that the gift of tongues was especially valuable and prominent. The Corinthian believers were able to better communicate the gospel and God’s Word as a result of the gift of tongues. However, Paul made it abundantly clear that even in this usage of tongues, it was to be interpreted or “translated” (1 Corinthians 14:13, 27). A Corinthian believer would speak in tongues, proclaiming God’s truth to someone who spoke that language, and then that believer, or another believer in the church, was to interpret what was spoken so that the entire assembly could understand what was said.

This is not in agreement with those who view praying in tongues as a prayer language. To give you a brief summary, there are many who believe that speaking in tongues is a special prayer language that only God can understand. They get this from 2 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. 3 But he that prophesieth speaketh unto men to edification, and exhortation, and comfort. 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 battle? 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 interpret.

Several question arise from this passage. 1 How could praying in tongues be a private prayer language is the scripture says it has to be interpreted? 
2) How could praying in tongues be for self-edification when Scripture says that the spiritual gifts are for the edification of the church, not the self (1 Corinthians 12:7)? 
3) How can praying in tongues be a private prayer language if the gift of tongues is a “sign to unbelievers” (1 Corinthians 14:22)? 
4) The Bible makes it clear that not everyone possesses the gift of tongues (1 Corinthians 12:11, 28-30). How could tongues be a gift for self-edification if not every believer can possess it?

Some understand praying in tongues to be a “secret code language” that prevents Satan and his demons from understanding our prayers and thereby gaining an advantage over us. This interpretation is unbiblical for the following reasons: 1) The New Testament consistently describes tongues as a human language, and Satan and his demons are well able to understand human languages. 2) The Bible records countless believers praying in their own language, out loud, with no concern of Satan intercepting the prayer. Even if Satan and/or his demons hear and understand the prayers we pray, they have absolutely no power to prevent God from answering the prayers according to His will. We know that God hears our prayers, and that fact makes it irrelevant whether Satan and his demons hear and understand our prayers.

What do we say, then, about the many Christians who have experienced praying in tongues and find it to be very personally edifying? 

First, we must base our faith and practice on Scripture, not experience. We must view our experiences in light of Scripture, not interpret Scripture in light of our experiences. 

Second, many of the cults and world religions also report occurrences of speaking in tongues/praying in tongues. Obviously the Holy Spirit is not gifting these unbelieving individuals. So, it seems that the demons are able to counterfeit the gift of speaking in tongues. This is not to say that all who speak in tongues are filled with demons. But what this should do is cause us to compare even more carefully our experiences with Scripture. 

Third, studies have shown how speaking/praying in tongues can be a learned behavior. Through hearing and observing others speak in tongues, a person can learn the procedure, even subconsciously. This is the most likely explanation for the vast majority of instances of speaking/praying in tongues among Christians. 

Fourth, the feeling of “self-edification” is natural. The human body produces adrenaline and endorphins when it experiences something new, exciting, emotional, and/or disconnected from rational thought. The key word here is emotional. 

Simply put, speaking in a language you have never learned is 100% an act of the Holy Spirit. This is not something that can be conjured up in our own flesh. Tongues always has been and always will be for edification of the body of Christ and the communication of the Gospel. If it has nothing to do with someone hearing the Gospel of Christ, there is no need for it!  Last time I checked, God can hear me in the English language that I speak.

There are those of certain denominations and communities that want to shame those who do not speak in tongues and consider them to be inferior because they do not share that experience.  Many have even declared that a person cannot enter into heaven without speaking in tongues.  

As a matter of personal note, I do not believe that speaking in tongues is a private prayer language that only God can understand nor do I believe that there is a necessity for tongues today. We have so many tools at our disposal to communication the Gospel. If you don't believe that.... All of us have language translation apps on our phones.

There are those who want to shame those who do not speak in tongues and even those who declare that a person cannot enter Heaven without speaking in tongues. I've got a good Greek word for that.....bologna!!

Scripture is clear on how we receive eternal life and that is to believe on the name of the Lord, Jesus Christ! Hallelujah! Not speaking in tongues or any other "thing" we can do. By grace alone, through faith alone, in Christ alone.