As a Linguist, I briefly took a look into the phenomenon of glossolalia. I can only offer a more linguistic (rather than religious) view of the phenomenon.
All the sounds produced by “speakers” are sounds that exist in the speaker’s native language or any other language the speaker is familiar with; i.e. it contains only those sounds already known to the speaker, thus the glossolalia of someone from say, India, is not going to sound anything like the glossolalia of someone from America. Pitch, accent, rhythm, and intonation is also used and typically represents the patterns of speech of the speaker’s own native language. These streams of speech are not internally organized and there does not appear to be any relationship between units of speech and the concepts they supposedly represent. Many syllables are repeated in various patterns. I don’t know if studies have gone so far as to try and determine if there is any substitution or changing of particular sounds or syllables with the given meaning the speech stream is said to mean (i.e. sort of like a very advanced “pig Latin” or so called “twin language”).
That aside, it is interesting how the speaker does not always seem to be able to “interpret” what s/he is saying. From a linguistic point of view, it’s interesting but essentially meaningless streams of speech which appear to be phonologically structured.
The Tower of Babel story is also quite interesting, particularly again from a linguistic viewpoint.
One must keep in mind that to a person living in what we know call the Middle East several thousand years ago, the “whole world” (being of one tongue) would have been just that; a small part of what we now call the Middle East.
Virtually all people in that neck of the woods spoke what we today call Semitic languages. Indeed, all of these languages were related and came from one source; a parent language called Proto-Semitic. Proto Semitic was, in turn, one of a few languages that split off from what is called Proto-Afro-asiatic.
The general consensus seems to be that Proto-Semitic had its ultimate origins in either Arabia, Mesopotamia or Africa.
Proto-Semitic subsequently splintered off (due to several factors, the main one being the migration of peoples to other areas and the general isolation of these peoples from one another over time) and developed into the various Semitic languages found in the ancient Middle East.
What is fascinating is that the fact that people recognized that there was indeed a parent language for the various languages they encountered (there would have been some mutual intelligibility between all of them for several hundred years) and seemed to preserve this in their oral tradition. The reasons for the splintering off of P-Semitic would not have been known to these people so they attributed it to God and the story of the Tower evolved as a way to explain this divergence in languages such that everyone could easily understand.
The biblical account is interesting in that, as mentioned, not only did people realize that all their languages were similar and thus must have come from one parent tongue, but they also seem to relate that these original speakers came from the East (which would stand to reason if P-Semitic did indeed originate to the east of what is now Israel, i.e. Arabia or Mesopotamia).
The biblical account as we have it today is one of very few ancient accounts of a people remembering the history of their language(s) - told of course in a religious context. If, however, the religious context is extracted, you end up with a pretty accurate historical account of what happened - speakers of Proto Semitic migrated towards the west and as they migrated and became isolated nations, groups, etc., their languages eventually splintered off into what would have been at first just dialects of P-Semitic, but over time, separate but a very closely related group of languages (the word for ‘god’ for example is essentially the same word in Hebrew “el” as it is in Arabic “allah” as it is in Assyrian and Babylonian (a/k/a Akkadian) “ilu”, Phoenician 'l, and Ugaritic 'il.
Surely ancient people would have realized they all must have come from the same source language (the Proto Semitic *'il).