Is speaking in tounges...

Right.

Moreover, speaking in tongues is not babbling jibberish. Why would Almighty YHWH cause His followers to babble?

Please read the scriptures about Pentecost:

Acts 2
The Coming of the Holy Spirit

1When the day of Pentecost arrived, they were all together in one place. 2And suddenly there came from heaven a sound like a mighty rushing wind, and it filled the entire house where they were sitting. 3And divided tongues as of fire appeared to them and rested on each one of them. 4And they were all filled with the Holy Spirit and began to speak in other tongues as the Spirit gave them utterance.

5Now there were dwelling in Jerusalem Jews, devout men from every nation under heaven. 6And at this sound the multitude came together, and they were bewildered, because each one was hearing them speak in his own language. 7And they were amazed and astonished, saying, "Are not all these who are speaking Galileans? 8And how is it that we hear, each of us in his own native language? 9Parthians and Medes and Elamites and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, 10Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, 11both Jews and proselytes, Cretans and Arabians--we hear them telling in our own tongues the mighty works of God." 12And all were amazed and perplexed, saying to one another, "What does this mean?" 13But others mocking said, "They are filled with new wine."​

In case you have any lingering doubts, pullverize, nuke, and eviscerate them. In the above passage from Acts 2, both the words "tongue" in v.3 and "language" in v.6 come from the same Greek word, Strong's Number 1258 "dialektos" (dialect). (FYI, "tongue" is the Germanic word, "language" is from Latin, but they both mean tongue, as in that fleshy muscle in your mouth; Germans say "tongue", Romans say "langue", just like Germans say "foot" and Romans say "ped".)

This is not a hard theological point. "Speaking in tongues" = miraculously speaking in foreign languages so that you can communicate the Gospel -- ie, do YHWH's Work -- more rapidly.

In modern terms, the Holy Spirit comes down upon you in a tongue of fire, and boom! you start speaking in Ugandan and head off on a missionary journey to Uganda. That's what it means. It does not mean you start babbling in gibberish.

Matthew 10:20
For *ye* are not the speakers, but the Spirit of your Father which speaks in you.