My friend is questioning the reason and need to speak “in tongues.”

The Biblical accounts I have read are of those doing this was at Pentecost, when the Lord distributed (gifted) the Christians with His voice to enable the listeners from different languages to hear in their own language—not gibberish. It was an outpouring to spread the word and testify to Jesus. My friend is questioning the reason and need to speak “in tongues” while praying, etc. I don’t doubt that our Father could allow this to happen, but I just don’t see biblical evidence that God requires His children to “learn a prayer language.” I am certain God ...