Why Pentecostalism is Wrong: Tongues as a Sign of Unbelief

Pentecostalism teaches that the gift and practice of speaking in unknown languages in the church today is a continuation of the outpouring of the Holy Spirit in Acts. But this view is fundamentally at odds with what scripture teaches about tongues. First and foremost, it misses what Paul says in 1 Corinthians 14 where he explains to the church that the gift of tongues was a sign for unbelievers. Quoting from Isaiah, Paul references the passage where God prophesied that he would speak to Israel in other tongues but even then, they would not hear.
What is also clear from Paul's teaching is that much of what he is referring to as speaking in tongues, would not mesh in any way with the Pentecostal practice today. Paul is using tongues to mean languages, and when he says to "speak in an unknown tongue", there is no reason to assume he means that somehow the speaker does not understand the tongue he is speaking in. When approached from this perspective, the meaning of these passages suddenly becomes much clearer, as Paul is obviously describing how to deal with the disunity and barriers to communication caused by those who cannot understand one another. Why is prophecy (declaring the truth of God's word) better than tongues? Because prophesying (declaring who God is) actually builds up the church, whereas the act of speaking in a different language, all by itself, does nothing, (and actually, speaking in a different language when no one else can understand you is actually a waste of time and can be more about showing off or exercising control by cutting people out of the conversation). Anyone who has ever traveled to a foreign country and needed to speak through an