About how much does language typology correlate with genetic relationships among languages? For example, should we expect most Sino-Tibetan languages to be isolating, or most Indo-European languages to have a lot of fusional affixes, and so on across language families?
About how much does language typology correlate with genetic relationships among languages?
Just to clarify: by "genetic relationships" you mean things like "sister language", etc. (not the actual DNA of the speakers)?– CerberusApr 28, 2012 at 5:46
4@Cerberus Yes, in historical linguistics 'genetic relationship' is commonly-used in this way. Sometimes the term 'genealogical relationship' is used to avoid this confusion with biological genetics.– Gaston ÜmlautApr 28, 2012 at 9:24
@GastonÜmlaut: Right, I have heard it used like that, but it always seemed a bit ambiguous, as you say, so I asked just to be sure.– CerberusApr 30, 2012 at 21:27
@Cerberus I think it's interesting to note that the ideas of a 'family tree', shared inheritance and descent with modification were originally developed in linguistics and later borrowed by Charles Darwin and his successors, as discussed at LanguageLog.– Gaston ÜmlautMay 2, 2012 at 5:49
@GastonÜmlaut: Oh, that is interesting, though "borrowed" sounds a bit strong: reading the quotation in the LL article, I get the impression that he simply compared the two rather than actively applying the model used in one field to another. Consider how everybody knew that animals could be bred to weaken and strengthen certain qualities, and how humans inherit certain features from their ancestors and pass them on: the general model of a family with descendants and ancestors and siblings was in common use. Darwin's comparison seems more like an illustration.– CerberusMay 2, 2012 at 6:47
Not very much, and what correlation there is can plausibly be put down to length of common development.
Note for example that while Slavonic and Baltic languages retain much of the inflectional apparatus of PIE (though most nominal inflection has been lost in South Slavonic), English and the Scandinavian languages have lost most of it. They haven't quite got to the point where you'd call them isolating, but they're getting somewhere near it.
The Sino-Tibetan languages are actually a wonderful counterexample. Some are isolating; some, especially the modern Tibetan languages, are agglutinative; and the Kiranti languages are highly fusional. Some are tonal; many aren't, including Newari and several of the Tibetan languages. (Indeed, Newari phonology looks like the phonology of an Indian language: voiced and voiceless aspirated plosives, retroflex and dental consonants, phonemic vowel length, and so on.) Some are SVO, but some, including the Tibetan languages again and also Burmese, are SOV.
It's important to remember that languages don't "know" what family they're in. A feature that's been part of the language for thousands of years is just as likely to stick around, and just as likely to be lost, as a feature that was just borrowed or innovated yesterday. So for instance, yeah, Mandarin and Newari share a common ancestor several thousand years back — but now there's nothing that's constraining them to evolve in the same direction as one another. And so in fact they've diverged tremendously, Mandarin coming to look like a "typical" East Asian language and Newari like a typical South Asian language.
To the extent that genetically related languages are typologically similar, it's a result either of historical intertia or of continued contact. Over the course of 4,000 years, historical intertia only buys you so much continued similarity. So when a language family spreads out over a natural barrier (as the Sino-Tibetan family did) or across a wide area (as Indo-European did), the result is an awful lot of typological diversity among genetically-related languages.
I cannot give an exact number of correlation, but the correlation between genetic relationship and typological features is strong enough to be annoying when one tries to construct an unbiased sample of the languages of the world. Picking just languages at random is not a good idea because a few very large language families (Austronesian, Niger-Kongo and Indo-Germanic) contribute a large bulk of related languages.
It is fruitful to include genetic relations between languages in typological studies, as demonstrated by Levinson, S., Greenhill, S., Gray, R., Dunn, M. (2011). Universal typological dependencies should be detectable in the history of language families. Linguistic Typology, 15(2): 509-534
What if we controlled for contact with each other? Dec 22, 2017 at 18:46
@A.M.Bittlingmayer: By contact, you mean geograohical contact in form of a common border? Well, then you pick the next neighbour and it is very probably still related. Dec 22, 2017 at 19:06
Not border distance as much as overlap area, and for which length of time. But it is just a rough measure. Dec 22, 2017 at 19:49
By control for it I do not mean eliminate it. Also you would need to account for common contact with a third language. Dec 22, 2017 at 19:51