Read Corinthians. You cannot help but see that the “unknown” tongues are nothing but foreign languages. Nothing more.
They appear to be foreign languages...
But then,,,, Paul says, 'tho I speak in tongues of men AND ANGELS,!!! What is that???
My conclusion based on 'not much' is that Adam was gifted with a language not only to speak to God with but his descendents as well...And I conclude from the verse that angels can converse with an actual language...
I have also concluded this language is probably Hebrew...
I find no language in the scriptures that justifies speaking in what Charismatics call tongues...