God enabled the apostles to speak in human languages that were previously unknown to them. Those who heard the apostles speak in tongues said that they heard them speak in their native tongues (Acts 2:1-11). This so amazed the hearers that they gave ear to the apostles, which was exactly Jesus’ intent for the miracle.

Imagine that you had a pen-pal from Zambia who came to visit you. You take them to your good buddy, Billy Bob, who is also a Christian, and he begins speaking to your Zambian friend in her native Zambian tongue. She would be so impressed that she would likely want to hear anything you or Billy Bob had to say. That’s the purpose of speaking in tongues. To show people that you are working with a power that comes from above and therefore your message is legitimate.

Imagine, however, that Billy Bob just starts spouting jibberish at your friend and claims it to be from God. What would you think? Anyone could do that. You can make up all the syllables you wanted to string together, but unless you speak an actual human language that everyone present knew you could not speak before, then what you spoke would be nonsense to them.

The miracles Jesus & his apostles did were obvious, powerful and undeniable just as some stated in Acts 4:13-16. Jibberish is none of those things.

Some try to call on 1st Corinthians 13:1 to claim that they are speaking in the languages of angels. It is a convenient claim because it cannot be checked or verified. Speak German and we can check that. Speak Mandarin Chinese or Portuguese, or any human language. That would prove there is a power working in you above yourself and you will have some credibility.

No apostle ever spoke in an angelic tongue. It would have been pointless as nothing could have been communicated. To speak jibberish and then attribute it to the Holy Spirit of God borders on blasphemy it seems to me.

Jesus’ apostle wrote in 1st Corinthians 13:8-11 that tongues, along with the ability to prophesy & have miraculous knowledge, would pass away. He said that they were like the childish things you put away once you have grown up.