The Lord doesn't refer to the language used to pray to the Lord in private and edify ourselves when there is no interpretation as "gobblely gook".
Groanings in words that can't be uttered - is not a "language". Why would you have the need to speak to God in a language you don't understand? If you speak something you don't understand; you're not speaking it to edify God. LOL
And who's to say what the apostles were saying was gobbley gook to themselves? If they intended to speak something in Aramaic that the hearer heard as Latin; They still understood what they intended to say. Even if they could not translate for the hearer into Latin.
Keep in mind that these gentile churches were filled with people of all types of linguistic backgrounds. So if someone stood up to proclaim the gospel to a foreigner and there was no one there to explain to the church what the message was; that was not to happen in a public venue.
What would the church have heard?
If the intent of the speaker was to speak Aramaic than those who would have known Aramaic would have heard Aramaic; those who did not understand Aramaic would not have understood what the speaker was saying; unless they had that gift where they would have heard the speaker in their own native language. Yet if they or anyone else could not communicate to the rest of the church in their native language; they were to keep silent.
Now if someone could translate; for the sake of order, there weren't suppose to be more than 3 speakers at any proclamation; coupled with subsequent translators.
So, if you have a congregation where there's 10 different native tongues; that would get chaotic rather quickly.
Then on the flip side; (which seems more plausible):
If you have a foreigner come in and proclaim what they'd heard to a group of people who had no way of understanding them; because they came from a location of an unknown tongue. (At least unknown to that group of people.) In that case, they need a translator. If no one can translate; then they are to be silent.
That seems like it would have happened a lot immediately after Pentecost.
You also have this scenario:
If the speaker spoke to the foreigner post service; they would have some idea of what they intended to say and the foreigner would hear them in their native language, but the two would not be able to carry on a conversation unless they both had the ability to speak and interpret; or unless there was a 3rd party interpreter.
In this way; you could have multiple proclamations and foreign translations of the gospel that would not cause disturbance during the actual service.
So if the speaker understood that this is how it worked; they might come up to the foreigner and say. "I have a message for you from God. I'm going to tell you about the death burial and resurrection of Jesus Christ and you will hear what I'm saying in the language you grew up with; yet I don't know your language, so we can't talk about what I say to you; unless God gives you the ability to speak in a language that I will hear you as in my language."
Now if they both have the gift of tongues; they can talk to each other and if in a public venue, also interpret what each is saying. That was probably not common though because if tongues are a sign for unbelievers; (though primarily Jews) the person receiving the message has probably not heard the gospel; and so would not be likely to have that gift.
That is a very different scenario from someone praying personally in a language they don't understand. There is no purpose for that because God is not bound by human language.
Yet if someone is to stand up and proclaim the gospel to a group of people who can't understand them; then the only one they are speaking to is God. But what's the point in that; He already knows what the gospel is!
