The Economics of "Why is it so hard to save a threatened Language?"

We study the language choice behavior of bilingual speakers in modern societies, such as the Basque Country, Ireland andWales. These countries have two o cial languages:A, spoken by all, and B, spoken by a minority. We think of the bilinguals in those societies as a population playing repeatedly a Bayesian game in which, they must choose strategically the language, A or B, that might be used in the interaction. The choice has to be made under imperfect information about the linguistic type of the interlocutors. We take the Nash equilibrium of the language use game as a model for real life language choice behavior. It is shown that the predictions made with this model t very well the data about the actual use, contained in the censuses, of Basque, Irish and Welsh languages. Then the question posed by Fishman (2001),which appears in the title, is answered as follows: it is hard, mainly, because bilingual speakers have reached an equilibrium which is evolutionary stable. This means that to solve fast and in a re ex manner their frequent language coordination problem, bilinguals have developed linguistic conventions based chie y on the strategy 'Use the same language as your interlocutor', which weakens the actual use of B.1