Anne Kandler: Santa Fe Institute

‘Language shift’ is the process whereby members of a community in which more than one language is spoken abandon their original vernacular language in favour of another. We model the dynamic of language shift as a Lotka-Volterra type competition process in which the numbers of speakers of each language and of the bilingual sub-population vary as a function both of internal recruitment (as the net outcome of birth, death, immigration and emigration), and of gains and losses due to language shift.

In order to test the model we apply our approach to the English-Gaelic competition in Western Scotland. We are able to replicate the main dynamic of the shift process and give predictions about the future of the Gaelic language under unchanged environmental conditions. However, the Gaelic language is subject to recent governmental interventions whose objective are stable societal bilingualism – by creating or preserving segregated sociolinguistic domains, in each of which one or other language is the preferred medium of communication. To consider these effects we examine a second model in which bilingualism is no longer simply a transitional state. Superimposed on the basic shift dynamic there is an additional demand for the endangered language as the preferred medium of communication in some restricted sociolinguistic domains.

The creation of segregated sociolinguistic domains can lead to stable co-existence and therewith be a successful maintenance strategy. Our model enables us to estimate e.g. for the English-Gaelic competition the strength of interventions needed in order to maintain the bilingual sub-population. Further, we analyse the crucial role of random drift for small numbers of speakers of the endangered languages and selective migration on the maintenance success.