in Danger lists Hokkaido Ainu as critically endangered with 15 speakers ... and both Sakhalin and Kuril Ainu as extinct." The language vitality for Ainu has weakened because of Japanese becoming the favoured language for education since the end of the nineteenth century. Education in Japanese heavily impacted the decline in use of the Ainu language because of forced linguistic assimilation. Language change The process of language change may also involve the splitting up of a language into a family of several daughter languages, leaving the common parent language "dead". This has happened to Latin, which (through Vulgar Latin) eventually developed into the Romance languages, and to Sanskrit, which (through Prakrit) developed into the New Indo-Aryan languages. Such a process is normally not described as "language death", because it involves an unbroken chain of normal transmission of the language from one generation to the next, with only minute changes at every single point in the chain. Thus with regard to Latin, for example, there is no point at which Latin "died"; it evolved in different ways in different geographic areas, and its modern forms are now identified by a plethora of different names such as French, Portuguese, Spanish, Italian, etc. Language shift can be used to understand the evolution of Latin into the various modern forms. Language shift, which could lead to language death, occurs because of a shift in language behaviour from a speech community. Contact with other languages and cultures causes change in behaviour to the original language which creates language shift. Measuring language vitality Except in case of linguicide, languages do not suddenly become extinct; they become moribund as the community of speakers gradually shifts to using other languages. As speakers shift, there are discernible, if subtle, changes in language behavior. These changes in behavior lead to a change of linguistic vitality in the community. There are a variety of systems that have been proposed for measuring the vitality of a language in a community. One of the earliest is the GIDS (Graded Intergenerational Disruption Scale) proposed by Joshua Fishman in 1991. A noteworthy publishing milestone in measuring language vitality is an entire issue of Journal of Multilingual and Multicultural Development devoted to the study of ethnolinguistic vitality, Vol. 32.2, 2011, with several authors presenting their own tools for measuring language vitality. A number of other published works on measuring language vitality have been published, prepared by