Glottochronology

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Glottochronology is a method in linguistics used to estimate the rate at which languages change, based on the assumption that the basic vocabulary of a language changes at a roughly constant rate. This assumption, originally put forward by Morris Swadesh, is based on an analogy with the use of carbon dating for measuring the age of organic materials, in that a "lexical half-life" is estimated. This is assumed to be the "average" time that any one word is in existence in a particular language. The method then estimates the length of time since two or more languages diverged from a common earlier proto-language, by seeing how many words have changed. This then yields an estimated date of origin for those languages. Glottochronology is a branch of quantitative linguistics.

1 Methodology
2 Controversy
3 Modified glottochronology
4 Bibliography
5 External links

[edit] Methodology

The original method presumed that the core vocabulary of a language is replaced at a constant (or near constant) rate across all languages and cultures, and can therefore be used to measure the passage of time. The process makes use of a list of lexical terms compiled by Morris Swadesh assumed to be resistant against borrowing (originally designed as a list of 200 items; however, the reduced 100 word list is much more common among modern day linguists). This core vocabulary was designed to encompass concepts common to every human language (such as personal pronouns, body parts, heavenly bodies, verbs of basic actions, numerals 'one' and 'two', etc.), eliminating concepts that vary by culture and time. Basically, glottochronology uses the percentage of cognates (words that have a common origin) in "basic word lists". The larger the percentage of cognates, the more recently the two languages being compared are presumed to have separated.

The basic formula for glottochronology in its shortest form is:

$t = \frac{\ln(c)}{-L}$

where t = a given period of time from one stage of the language to another, c = percentage of 100-wordlist items retained at the end of that period, and L = rate of replacement. By testing historically verifiable cases where we have knowledge of t through non-linguistic data (e. g. the approximate distance from Classical Latin to modern Romance languages), Swadesh arrived at the empirical value of approximately 0.14 for L (meaning that the rate of replacement constitutes around 14 words from the 100-wordlist per millennium).

[edit] Controversy

[edit] Mainstream rejection

Since its original incarnation, glottochronology has been rejected by many linguists who view it as having been falsified by many counterexamples. Many claim there is enough evidence to support the idea that languages change at varied rates. For instance, a language's literature may have a stabilizing effect on a literate culture's language (McWhorter page number needed). Another argument is that language change arises from socio-historical events which are unforeseeable and uncomputable. Since these changes take time, they might appear as varying rates.

[edit] Pseudo-Falsification

Some of the more common examples used to discredit glottochronology are actually based on an incorrect understanding of the method. Glottochronology does not presume that language as a whole always changes at a stable rate (including its phonology or grammar), nor does it deny the possibility of rapid lexical loss in the "cultural" layer of the lexicon under specific circumstances. Instead, it places its primary focus on a small, strictly defined list of the most basic items that, according to proponents of the method, do turn out to be resistant to rapid change.

For example, English did not replace about 50 % of its originally Germanic vocabulary 'by time', but, as educated speakers of English know, by Norman dominance after the battle of Hastings, besides a long-lasting educational background of Latin. Nevertheless, within the Swadesh 100-wordlist there is but one English item owed to effects of the Norman conquest ('mountain'), meaning that in terms of a short list of basic lexicon these effects can be all but neglected.

Another example is Albanian, which changed 90% of its Indo-European heritage, while the neighbouring Greece did not. Yet at the same time in terms of the 100-wordlist both Albanian and modern Greek share approximately the same number of cognates between themselves and select Indo-European languages from other branches (with English, for instance - around 25-26 percent), which, again, shows that the basic lexicon of Albanian shifted far less dramatically than the "cultural" part of it.

[edit] Real Falsification

Much more problematic for glottochronology was the critique addressed at its true foundation, when the method turned out to be falsifiable by using Swadesh's own rules. Thus, in Bergsland & Vogt 1962 the authors managed to make an impressive demonstration, on the basis of actual language data verifiable by extra-linguistic sources, that the "rate of change" for Icelandic constituted around 4% per millennium, whereas for Riksmal (Literary Norwegian) it would amount to as much as 20%. (Swadesh's proposed "constant rate" was supposed to be around 14% per millennium).

This and several other similar examples effectively proved that Swadesh's formula would not work on all available material - a serious accusation considering that evidence that can be used to "calibrate" the meaning of L (i. e. language history recorded during prolonged periods of time) is not overwhelmingly large in the first place. As a consequence, many linguists turned away from glottochronology entirely, rejecting it as falsified once and for all.

[edit] Modified glottochronology

Somewhere in between the original concept of Swadesh and the rejection of glottochronology in its entirety lies the idea that glottochronology as a formal method of linguistic analysis becomes valid with the help of several important modifications. In particular, an attempt to introduce such modifications was performed by the Russian linguist Sergei Starostin, who had proposed that

systematic loanwords, borrowed from one language into another, are a disruptive factor and have to be eliminated from the calculations; the one thing that really matters is the "native" replacement of items by items from the same language. The failure to notice this factor was a major reason in Swadesh's original estimation of the replacement rate at around 14 words from the 100-wordlist per millennium, when the real rate is, in fact, much slower (around 5 or 6). Introducing this correction effectively cancels out the "Bergsland & Vogt" argument, since a thorough analysis of the Riksmal data shows that its basic wordlist includes about 15-16 borrowings from other Germanic languages (mostly Danish) - exclusion of these elements from the calculations brings the rate down to the expected rate of 5-6 "native" replacements per millennium;
the rate of change is not really constant, but actually depends on the time period during which the word has existed in the language (i. e. chances of lexeme X being replaced by lexeme Y increase in direct proportion to the time elapsed – the so called "aging of words", empirically understood as gradual "erosion" of the word's primary meaning under the weight of acquired secondary ones);
individual items on the 100 wordlist have different stability rates (for instance, the word "I" generally has a much lower chance of being replaced than the word "yellow", etc.).

The resulting formula, taking into account both the time dependence and the individual stability quotients, looks as follows:

$t = \sqrt \frac{ln(c)}{-Lc}$

In this formula, -Lc reflects the gradual slowing down of the replacement process due to different individual rates (the less stable elements are the first and the quickest to be replaced), whereas the square root represents the reverse trend - acceleration of replacement as items in the original wordlist "age" and become more prone to shifting their meaning. The formula is obviously more complicated than Swadesh's original one, but, as shown in Starostin's work, yields more credible results than the former (and more or less agrees with all the cases of language separation that can be confirmed by historical knowledge). On the other hand, it shows that glottochronology can really only be used as a serious scientific tool on language families the historical phonology of which has been meticulously elaborated (at least to the point of being able to clearly distinguish between cognates and loanwords).

[edit] Bibliography

Arndt, Walter W. (1959). The performance of glottochronology in Germanic. Language, 35, 180-192.
Bergsland, Knut; & Vogt, Hans. (1962). On the validity of glottochronology. Current Anthropology, 3, 115-153.
Callaghan, Catherine A. (1991). Utian and the Swadesh list. In J. E. Redden (Ed.), Papers for the American Indian language conference, held at the University of California, Santa Cruz, July and August, 1991 (pp. 218-237). Occasional papers on linguistics (No. 16). Carbondale: Department of Linguistics, Southern Illinois University.
Gudschinsky, Sarah. (1956). The ABC's of lexicostatistics (glottochronology). Word, 12, 175-210.
Hockett, Charles F. (1958). A course in modern linguistics (Chap. 6). New York: Macmillan.
Hoijer, Harry. (1956). Lexicostatistics: A critique. Language, 32, 49-60.
Holm, Hans J. (2003). The Proportionality Trap. Or: What is wrong with lexicostatistical Subgrouping.Indogermanische Forschungen, 108,38-46.
Holm, Hans J. (2005). Genealogische Verwandtschaft. Kap. 45 in Quantitative Linguistik; ein internationales Handbuch. Herausgegeben von R.Köhler, G. Altmann, R. Piotrowski, Berlin: Walter de Gruyter.
Hymes, Dell H. (1960). Lexicostatistics so far. Current Anthropology, 1 (1), 3-44.
Lees, Robert. (1953). The basis of glottochronology. Language, 29 (2), 113-127.
McWhorter, John. (2001). The power of Babel. New York: Freeman. ISBN 0-7167-4473-2.
McMahon, April and McMahon, Robert (2005) Language Classification by Numbers. Oxford: Oxford University Press.
Sjoberg, Andree; & Sjoberg, Gideon. (1956). Problems in glottochronology. American Anthropologist, 58 (2), 296-308.
Starostin, Sergei. Methodology Of Long-Range Comparison. 2002. pdf
Swadesh, Morris. (1955). Towards greater accuracy in lexicostatistic dating. International Journal of American Linguistics, 21, 121-137.
Swadesh, Morris (1972). What is glottochronology? In M. Swadesh, The origin and diversification of languages (pp. 271–284). London: Routledge & Kegan Paul.
Tischler, Johann, 1973. Glottochronologie und Lexikostatistik [Innsbrucker Beiträge zur Sprachwissenschaft 11]; Innsbruck
Time Depth in Historical Linguistics (2000). Ed. by Colin Renfrew, April McMahon & Larry Trask. The McDonald Institute for Archaeological Research, Cambridge, England.