I was recently asked evaluate a mathematical model of language death as language competition from an Ask-A-Linguist panel. The paper referred to was Modelling the Dynamics of Language Death (Nature, 2003). It’s an interesting idea…in theory, but does it work and does it tell anything new?

This particular paper (actually a “Brief Communication”) proposes an equation to model decline in speaker population for Scottish Gaelic, Welsh and Quechua. I will presume that the equation they derived closely matches observed data found in their census figures.

What I’m not entirely certain is how certain variables, such as “Status” were derived. As they note, status is an important factor apart from sheer number of speakers. Without understanding how a status index is determined it’s hard to evaluate how this model would predict decline in the future.

Which Factors?

In fact I would say that “Status” can be tricky to define. Sometimes status can be equated to political power, but not always. There are cases where a language of the political elite ends up dying in a region because the rulers switch to the language of the populace. English survived Norman French (several centuries worth) and Greek survived the Latin speakers of the Roman Empire although it succumbed to Ottoman Turkish (except in Greece).

The authors mention another factor of “mixing”, but it does not appear to be factored in as an official parameter that I could determine. One factor which allowed Welsh to survive under a non-Welsh government was those most people in Wales were monolingual, meaning that relatively fewer people felt the need to be bilingual in English and Welsh. Today urbanization and mass media in a relatively small number of languages changes that. If you want to watch a televised soap opera, your language options are still limited.

Similarly, speakers or voluntarily emigrate to new communities may often have children who speak languages, although sometimes new community nuclei (e.g. Chinatowns) can emerge, at least for a few generations. Because this model only studies the effects of populations in situ, it can’t take the effects of a literal population move (or disapora) into account and determine if they are relevant factors.

Another very important factor not mentioned is whether there is an ongoing language elimination campaign. It is possible for minority communities in the same location to remain bilingual…if they are tolerated by the local government. For instance, Pennsylvania German, the language of the Amish is not only living, but expanding in the U.S. (Page, personal communication). But we know from North America, Australia and the U.K. that a lot of languages lost speakers when the children were forced to be educated in English only (or French only in the Breton). Similarly, outlawing publications or official communication in a minority language will cause the “status” of the dominant language to artificially rise. Forced deportations and separations have similar effects.

Other Cases

Finally, I would say that there are mysteries of language life and death that any model of language death and survival must answer. One is why Norman French was eliminated in favor of the less prestigious (but more numerous) English. Compare with Peru where Quechua has not yet overtaken Spanish in any realistic way, although there are still many speakers remaining. Another is predicting the spread of Arabic through Egypt (dominating Coptic), Iraq and North Africa (wiping out Latin), but NOT further east. What combination factors are important? Is religious belief a factor after all? Is intermarriage a factor?

I do think that it’s possible to mathematically model this, but I think it’s important that the linguistics be taken as seriously as the math. I applaud the efforts of the authors, two fine applied mathemeticians, but I don’t believe that census figures and a simple “status” index alone can tell the entire story. I would want to know more about the specific factors.

A Final Warning

I would end this discussion by pointing out that no language can really be considered “permanently” safe. Egyptian was the language of a power for several millennia before they were ultimately conquered by the Romans. Even then, late Egyptian survived long enough to become the basis of the Coptic church, but eventually Arabic came to dominate in Egypt. Coptic now survives as mostly a liturgical language, but Egyptian was spoken a lot longer (3000+ years) than it has been “dead” (ca 1000-500) years.

According to this Web history, Coptic too was a subject of a deliberate language elimination campaign…just like Welsh and Breton.