245 14 Towards an understanding of language distribution in the Tani area: Social organization, expansion and migration YANKEE MODI Universität Bern 1 Introduction everal scholars have argued for a causal relationship between large-scale adult second language acquisition and a ‘simplified’ or ‘creoloid’ language structure, which lacks many grammatical ‘extras’ like gender, agreement, and so on (McWhorter 2007, Trudgill 2009, among others). This idea has entered the Tibeto-Burman literature beginning with Burling (2007), who discussed cases in which creoloid languages are used as lingua francas in the Tibeto- Burman area, and become reshaped as a result of this use. DeLancey later fo- cused Burling’s argument on the process of state formation, arguing that the spread of lingua francas in the context of state formation in the Tibeto-Burman area led to the simplification of languages like Tibetan, Proto-Boro-Garo, and Old Chinese as these languages were acquired by adults in large subject popula- tions. Meanwhile, a more archaic morphological type is retained by many hill languages such as Kiranti, rGyalrongic, Kuki-Chin and Tangsa, whose speakers remained basically independent of states until well into the modern era (DeLancey 2010, DeLancey 2011, DeLancey 2012, DeLancey 2013). These are compelling hypotheses, since they have the potential to explain structural dif- ferences among Tibeto-Burman languages as resulting in part from the social histories of human populations. But there are also some problems. For example, the Tani languages, which are primarily spoken in a remote and mountainous section of the central Eastern Himalaya, mostly exhibit the same creoloid language profile that Boro-Garo and Tibetic languages have. According to Post (2015), the proto-language Pro- to-Tani looks like it has an even more strongly creoloid profile, which closely resembles languages of the Jingpho group, discussed by Burling and DeLancey. However, there is no history of state formation in the Tani area, and in fact, S