Oh, its a shame I didn't read this thread earlier. I've read some really neat stuff recently about languages...mostly because im taking a Communications Studies major at University. So this is all neat stuff.
Genetic stuff is complete and utter garbage as far as I'm concerned and everything I read indicates. But its very easy to explain why one group of people would find it very difficult to say something "natively" in another area (taking from the example above). The reason is because babies, almost as soon as they gain their vision (because you don't have perfect 20/20 vision right off the bat) watch the facial movements of their parents. They have already heard their mother speak for quite a few months (in and out of the womb) and the vibrations have become familar. Apparently its a very fast process where a baby picks up on the facial movements of their parents and this is why they will form the same patterns of speech.
Now as to glyphs and alphabets, thats probably an unanswerable question. Chineese for instance (and there is probably a whole bunch of variations, so I'll just generalize) is actually somewhat more direct than the western alphabet is. Its far less arbitrary because the symbols actually have visual meanings. But in English, French, German and others, the letter A has very little intrinsic value if any. The words "Table" or "House" mean little if you don't know what they are supposed to represent.
As far as FreeSpace's Vasudans go, its quite possible that two things exist.
1) A "local" dialect of language that exists in some more remote areas.
2) A more universal language that exists on all of Vasuda Prime (speaking before the Lucifer bombardment). Now Vasudan language is very interesting and complex as it relates to the time of day I think and your position from the Emperor and all of that. SO its

more fluid and confusing for an outsider to pickup on.
Probably Terrans are the same thing by the time of FreeSpace and its possible that we will go the same way as well. English is slowly becoming one of the most written (in any case) language in the world because of the Internet. Now regardless of if its English or another language, the Internet is starting to bring

of people together and whats the point if they can't all understand each other.
So, technology is going to do one of two things.
1) Its going to largely unify languages in a hundred or two hundred years. If only because everyone needs to be able to understand each other.
2) Technology is going to make it possible for everyone to speak/write in their own language and then run through a highly complex (not yet invented) translator which will translate between languages instantaneously and prefectly so that everyone is able to communicate their ideas anyways.
So either technology will force everyone to use the same language, or it will preserve languages and allow more people to use their own language (provided its in the translator).