According to most linguists, Korean is a language isolate. Why doesn't it have any sister languages, like languages usually do? Why didn't it spread to other areas, or split into various languages? The speakers are not geographically isolated from other areas (unlike Japan, for example), and they also have relatively large number of speakers. What are the historical factors that caused its isolation?
I think this question represents a certain confusion of terminology. By definition, a living language does not have daughters (excluding some circumstances where a parent language is retained in a particular use after the spoken languages have moved on and split, as with Latin, Sanskrit, Classical Arabic, etc.) So the question should not be "Why doesn't Korean have daughters?" as much as "Why doesn't Korean have sisters (other languages descended from the same parent)?"
With that in mind, here are some points:
- Korean does exhibit dialectical differences. It isn't exempt from the process of language change.
- Modern Korean is descended from Old Korean, which was probably one of the Buyeo languages. As the name suggests, there were several languages spoken in the Korean peninsula at this time, which are believed to be descendants of the unattested Proto-Korean.
- The fact that there is only one language currently spoken on the Korean peninsula appears to be because one dialect gained enough prestige to eliminate its competitors. In other words, Modern Korean is an isolate because it killed off its sister langs. The timing of this sororicide is unknown, but probably occurred during the unification of Korea in the Middle Korean period (my speculation).
Edit: One more thing: I doubt whether it's actually a case for a language to "normally" have sisters or daughters. All languages change, but language change only results in language split if the original speaker community has spread out enough to lose frequent inter-communication. The number of languages that expand rapidly in this sense is actually rather small, though the fact of their expansion means that they represent a large fraction of all language speakers.
So it seems most accurate to say that most languages have no daughters (or only one daughter, depending on how you look at it), but that most languages are descended from languages that have many daughters. In this sense, language isolates are "normal", while the big language families that we're familiar with are the result of some "abnormal" period of historical expansion.
2Ack, even when they're in quotes, the terms "normal" and "abnormal" seem inappropriate in this context.– mollyocrSep 19, 2011 at 16:31
1I don’t really see how you can seriously say that language isolates are “normal” given their obvious rarity. The vast majority of languages, from widely-spoken modern literary languages all the way to unwritten aboriginal/bushman languages come in families, and such relatedness appears to occur all over the world. From what I can see, the Korean language is rather the exception than the norm.– TimwiSep 20, 2011 at 23:53
1@Timwi: I think JSBangs means that, if you count the total number of language families that have ever existed and you count language isolates as one family each, the share of isolate "families" would be very high. I am not sure about that theory; but we shouldn't be mislead by looking at the total number of (extant or extinct) languages or numbers of speakers.– CerberusSep 21, 2011 at 1:13
3@Timwi: The majority of the living languages in the world are found in Papua New Guinea, Australia, and the Americas, and of those the majority are isolates, or grouped into very uncertain and highly controversial families. So I'd wager that the majority of the world's languages are isolates, and that the proportion would be even higher if we had access to prehistoric language data.– JSBձոգչSep 21, 2011 at 13:31
3I strongly disagree with JSBᾶngs that the majority of languages are/would be isolates. Such a claim shows lack of understanding how languages are genetically classified and why there are language isolates in the first place. Incidentally, the usual number given in literature is 350, and Lyle Campbell convincingly argues that it's actually 129, which makes 37% of all language families. www2.hawaii.edu/~lylecamp/CAMPBELL%20BLS%20isolates.pdf– Alex B.Nov 13, 2011 at 15:40
My understanding of a language isolate is a language that has no relationship with another language, which means that it does not share a common ancestor with another language. (JSBãngs said it well above.)
KO may be an isolate, it may be a member of the Altaic family, it may part of a Sprachbund, or a combination of these. (It's not unheard of that sometimes languages that share a common ancestor later are part of the same Sprachbund too, like in the Balkans.)
The World's Major Languages gives a concise historical background of KO language and the theories of its origins here. (It's very interesting to me because in addition to discussing the linguistic features that KO shares with Dravidian languages, the Austronesian languages and the Altaic languages, it also mentions anthropological and archaeological evidence for each of these theories.)
In short, its siblings, if it had any, died out.
2Or merged. Probably a bit of both. More distantly related languages would've died out or diverged, more closely related languages would've coalesced or died out. Sep 20, 2011 at 21:15
I was under the impression that all languages are considered isolates until it's demonstrated to a high degree of certainty that they're related to another language. Was I wrong on this?
There've been various attempts at linking Korean to Japanese and Ainu, on one-hand, and to the Turkic-Mongolic languages on the other. Should the proponents of one of these efforts succeed, then Korean would stop being classified as an "isolate", which really means "not enough data to accurately say if it's related to something else or not".
2I don't know if even Turkic and Mongolic are accepted to be related. I'm studying Mongolian in UB right now and it does feel a lot like Turkish, Japanese, and Korean which I've also studied. But none of them seem to share lexicon. Dec 20, 2013 at 15:32
It is not language isolate. It is related to Japanese and Ainu and the three along with others belong to Altaic family.
8This is only one theory out of several. One problem with declaring a genetic relationship between Japanese (let alone Ainu) and Korean is the extreme scarcity of reliable cognates. Vovin's "Koreo-Japonica" is a review of hundreds of claimed Japanese/Korean cognate roots, and unfortunately the conclusion for all but a handful of roots is that the strength of the relationship is weak or unclear. The strong similarity in grammar can be explained as more recent Sprachbund effects.– jogloranNov 13, 2012 at 0:56
I think most consider this theory discredited. Nov 20, 2017 at 15:46