Having been invoked by the most excellent Palewriter, I must respond! ;D
There are some excellent threads on this subject, which, as always, I myself am too lazy to look up. I heartily encourage anyone with more patience than I to seek them and post links.
Anyway, while we await such a person:
I’m not sure how fully my beloved tagline answers the question, though it certainly is relevant. It is hard to pinpoint exactly when what used to be merely a dialect becomes a new language in its own right, distinct from the older language that it developed from. Often the distinction is as arbitrary as just who has the armed forces to ensure that everyone else within their borders acknowledges the "purer" dialect as an independent language, whether or not there is any linguistic evidence to support that distinction.
That being said, it is true that all natural human languages, as far as we can tell, are the result of the gradual modification over time of older existing languages. For example, the language spoken in England many centuries ago, which we now call Old English, was extremely different from anything we in modern times would recognize as English; if anything, it looks like German, though a speaker of modern German would probably find it very difficult to understand as well. Over the course of centuries, Old English underwent many changes, and became Middle English, which modern English speakers can understand somewhat when reading, but which would not be understood much if heard spoken aloud. More centuries passed and the language became modern English, various dialects of which are spoken today in many countries throughout the world. (This is all a bit of an over-simplification, but more in-depth explanations can be found elsewhere around here.) However, even though it has changed very much over hundreds of years, English is still considered to be a Germanic language, not because modern German is its "mother" language, but because there was a very ancient language long ago that people in northern Europe spoke, and over time their descendents’ dialects changed, so that they became English, German, Danish, Swedish, and several other languages. All these languages are considered to be related to each other - no one of them is the "mother" of the other, but they all come from a "mother" language that was spoken many centuries ago. So they could all be considered "sister" languages, or at least cousins.
Similar histories exist with the Romance languages, which developed from Latin (Spanish, French, Italian, etc.), and the languages of India, many of which (though not all) are descendents of Sanskrit. While some other languages’ family trees are harder to trace than others, there is no reason to believe that they don’t exist.
Enough writing for one night. I shall now depart for sleep, and leave others to add further comments. ;D
~Silver
Anyone got a sleepy smiley?
