Dialectal Layers in West Iranian: a Hierarchical Dirichlet Process Approach to Linguistic Relationships

This paper addresses a series of complex and unresolved issues in the historical phonology of West Iranian languages. The West Iranian languages (Persian, Kurdish, Balochi, and other languages) display a high degree of non-Lautgesetzlich behavior. Most of this irregularity is undoubtedly due to language contact; we argue, however, that an oversimplified view of the processes at work has prevailed in the literature on West Iranian dialectology, with specialists assuming that deviations from an expected outcome in a given non-Persian language are due to lexical borrowing from some chronological stage of Persian. It is demonstrated that this qualitative approach yields at times problematic conclusions stemming from the lack of explicit probabilistic inferences regarding the distribution of the data: Persian may not be the sole donor language; additionally, borrowing at the lexical level is not always the mechanism that introduces irregularity. In many cases, the possibility that West Iranian languages show different reflexes in different conditioning environments remains under-explored. We employ a novel Bayesian approach designed to overcome these problems and tease apart the different determinants of irregularity in patterns of West Iranian sound change. Our methodology allows us to provisionally resolve a number of outstanding questions in the literature on West Iranian dialectology concerning the dialectal affiliation of certain sound changes. We outline future directions for work of this sort.Comment: 28 p

Modeling linguistic evolution : A look under the hood

This paper takes a detailed look at some popular models of evolution used in contemporary diachronic linguistic research, focusing on the continuous-time Markov model, a particularly popular choice. I provide an exposition of the math underlying the CTM model, seldom discussed in linguistic papers. I show that in some work, a lack of explicit reference to the underlying computation creates some difficulty in interpreting results, particularly in the domain of ancestral state reconstruction. I conclude by adumbrating some ways in which linguists may be able to exploit these models to investigate a suite of factors which may influence diachronic linguistic change

Iranian Dialectology and Dialectometry

This dissertation investigates the forces at work in the formation of a tightly knit but ultimately non-genetic dialect group. The Iranian languages, a genetic sub-branch of the larger Indo-European language family, are a group whose development has been profoundly affected by millennia of internal contact. This work is concerned with aspects of the diversification and disparification (i.e., the development of different versus near-identical features across languages) of this group of languages, namely issues pertaining to the development of the so-called West Iranian group, whose status as a legitimate genetic subgroup has long remained unclear. To address the phenomena under study, I combine a traditional comparative-historical approach with existing quantitative methods as well as newly developed quantitative methods designed to deal with the sort of linguistic situation that Iranian typifies. The studies I undertake support the idea that West Iranian is not a genetic subgroup, as sometimes assumed; instead, similarities between West Iranian languages that give the impression of close genetic relatedness have come about due to interactions between contact and parallel driftlike tendencies. I develop new methodologies which make it possible to demonstrate which similarities are due to contact and which are due to drift

Linguistic stability and change under small-scale egalitarian language contact : a mixture model approach

This paper investigates the outcomes of small-scale egalitarian language contact in an attempt to address whether different linguistic domains exhibit different degrees of stability and resistance to convergence among cohabitant speakers of Jahai and Jedek, two closely related Aslian (Austroasiatic) language varieties spoken in northern Peninsular Malaysia. Using nonparametric Bayesian mixture models, we find that basic vocabulary items show a signal that strongly matches the linguistic identity of individuals, while data from other domains do not. This result is in agreement with other findings from the study of language contact: basic vocabulary is said to be a domain where distinctions in linguistic identity are often emphasized and maintained, while other parts of the vocabulary may be less salient for the purposes of indexing speaker identity, and are thus more prone to the effects of convergence. We demonstrate that this finding is an artifact of neither data coverage nor model choice; at the same time, we are able to identify variation in basic vocabulary items across linguistic groups which is suppressed by the model we use, and outline alternative methods for analyzing data of this sort