No, speaking in tongues in Pentecostalism is not meant to be understood literally, because it was a metaphor for the mission of the church. The Holy Spirit meant that people would be given the skills to go speak to people in a variety of countries and cultures about Jesus Christ and the plan of salvation.
When those in a Pentecostal church talk about speaking in tongues, they are alluding to the fact that our rational minds can keep us from experiencing the deeper divinity. So they let their rational minds be suspended so that the unconscious can relate to the spirit and express that connection.
"Speaking in tongues" in Pentecostalism is not meant to be understood literally. The Pentecostalists believe that speaking in languages unknown to humans, or simply speaking gibberish is considered a gift from the Holy Spirit. In order for "speaking in tongues" to be understood literally it must involve a person being able to speak in a earthly language that was previously not known to them. This is considered is a gift from the Holy Spirit because the person can communicated in a language that they never studied before, so it is a gift in the form of knowledge. Speaking gibberish does not qualify as a gift from the Holy Spirit.
No, it is just saying that you are speaking a lot of different languages, it is not saying that your are speaking in your tongue. It is supposed to be god speaking through you in his ancient language, but it is actually all face and it is just an act.
The pentacostals that believe in speaking in tongues will testify that the vocalizations that result from "God's presence" are not any language that could be understood. These vocalizations are much like the static that results from an encrypted voice message on radio waves. The only person able to understand them must have the cypher, and according to the pentacostals, only God and the Angels have that.