It's surprising to me what a powerful an interest we have in our origins, surprising because we all have the same ultimate origin in fact (the African genesis of all people seems to be holding up), and surprising, too, because the sorts of things that concern us don't make any difference. History's done and dusted, so to speak. And while it might be a good thing to know the past so that in politics we don't repeat our mistakes more than a few hundred times, there's nothing we can do about who we are as individuals, as tips of branches on the family bush — apart from those relatively few cases, of course, where there's concern about a heritable disease or condition. But still we want to know if we're Celtic, whether (like me) there's a jewel thief in our background, who our biological father was, and what part of Africa we came from.
It's the same with languages. They, too, have "families" and we concern ourselves with linguistic family trees, of which there are dozens and dozens — the largest of which, fittingly, is the Niger–Congo family embracing more than 1,500 offspring; and there are something like three-dozen families of North American indigenous languages, for instance, and more than fifty in South America.
One such family of languages, the one to which English belongs, has the surname Indo-European. It sits in the fifth position as progenitor, having spawned 439 tongues. (Actually, I think it's more correct to say that the progenitor is a reconstructed ancestor, Proto Indo-European, which is none of the child languages and no existing language — indeed, a pre-historic language, i.e. one of which there is no written record, from about 8,000 BC.) Wikipedia has a fascinating chart that shows the rough relationships among this medium sized family of chat.
But it's origins we're focusing on for the moment, not proliferation as such. And the big debate among linguistic archeologists has been whether to place the root of the proto Indo-European tree in the Anatolian peninsula (roughly where Turkey is now) or on the steppes near the Caspian Sea. Computers may have come close to resolving the debate, according to an article in the Economist, pointing to Anatolia as our linguistic home. (But scientists being as argumentative as they are, the debate may not be over: see the featured comment — and others chauvinistically boosterish about Indians, Arabs, Chinese, etc. etc.) There's a brief description of the method in the Economist piece, and associated with the article in Science a list of words whose cognates in other languages point to a common ancestor and to a location for that ancestor.
Most interesting, perhaps, for those of us not versed in linguistics or mathematical modelling, is the QuickTime movie of how our language family spread across Europe and parts of Asia. (The film runs a little quick, and I find it's best to let it load and then step through the "ages" by clicking along the progress bar.)
So Punjabi, Icelandic, Gaelic, and Greek — all cousins (only) a few hundred times removed. But not related to Kannada, Finnish, Georgian, or — incongruously, since it now dominates the Anatolian peninsula — Turkish.