The riddle of Tasmanian languages

Claire Bowern * 0 0 Department of Linguistics, Yale University , 370 Temple Street, New Haven, CT 06511 , USA Recent work which combines methods from linguistics and evolutionary biology has been fruitful in discovering the history of major language families because of similarities in evolutionary processes. Such work opens up new possibilities for language research on previously unsolvable problems, especially in areas where information from other sources may be lacking. I use phylogenetic methods to investigate Tasmanian languages. Existing materials are so fragmentary that scholars have been unable to discover how many languages are represented in the sources. Using a clustering algorithm which identifies admixture, source materials representing more than one language are identified. Using the NeighborNet algorithm, 12 languages are identified in five clusters. Bayesian phylogenetic methods reveal that the families are not demonstrably related; an important result, given the importance of Tasmanian Aborigines for information about how societies have responded to population collapse in prehistory. This work provides insight into the societies of prehistoric Tasmania and illustrates a new utility of phylogenetics in reconstructing linguistic history. 1. INTRODUCTION The indigenous people of Tasmania were severely affected by European settlement in the nineteenth century [1]. Although it is known from ethnographic sources and early reports [2] that Indigenous Tasmanians comprised 48 bands in nine tribes [3,4] (figure 1), the number of languages and their internal phylogenetic relationships have remained a mystery. Previous work [5 9] has identified anywhere from a single language [5] to as many as 12 [6]. Despite the dearth of information about them, Tasmanian Aborigines have long held an important place in anthropology [10 12]. Their toolkit, for example, was the simplest of any attested group in the nineteenth century, and they are often cited as an example of how population collapse may also lead to technological collapse and societal decomplexification [10,11] (the so-called Tasmanian effect). Information from language has thus far been underused in studying Tasmanian society; nonetheless, it provides an important window on Tasmanian internal diversity. The linguistic information may, indeed, be the only investigable source for Tasmanian heterogeneity at the level of the whole island. The anthropological, archaeological and genetic data are all insufficient here. Ethnographically, Ryan [4] describes Tasmanian tribes as a single culture bloc with extensive shared practices and beliefs (such as star gods and the evil spirit Wrageowrapper), and a common toolkit. Jones [13] provides evidence for a strong cultural boundary between eastern and western Tasmania, but also notes many shared practices across the island. While recognizing nine distinct tribes, both Ryan & Jones [3] focus on the documentation of exchange networks and seasonal travel which reinforce reciprocal links across the island. Other work assumes a monolithic view of Tasmania without discussion [14]. The archaeological record is patchy, with few Pleistocene sites [15]; moreover, Tasmanians did not have a rich material culture and the Tasmanian climate is not conducive to long-term preservation of wooden artefacts. There is, however, some evidence of internal diversity in the archaeological record (for example, the abandonment of rainforest sites after the Late Pleistocene [16] and the expansion of people down the western coast over the last 3000 years [13]). Within genetics, there is not sufficient genetic information to be able to determine any differences between Tasmanian populations, and subsequent history has led to sufficient European admixture that such work is not possible. There is, however, work which compares genetic data from Tasmanians with other populations [17,18], including those from Australia, such as Presser et al. [19], who find evidence of mitochondrial DNA links between Tasmania and the mainland. It is known that the Tasmanian population underwent a population crash following the flooding of Bass Strait at the end of the Last Glacial Maximum [13], approximately 12 000 years ago. The population remained well below carrying capacity and was only recovering at the time of European colonization. Presumably, the Early Holocene population collapse led to a reduction in linguistic diversity on the island. It is not known, however, whether rates of language diversification were rapid enough to obliterate any evidence of a bottleneck, or whether the current languages and families show a common ancestor which predates the flooding of Bass Strait. If the data show that Tasmanian languages most probably belong to a single family, this would provide good evidence for slow rates of change in small societies, since there is no evidence for population replacement during the Holocene. However, it is also possible that any evidence for a linguistic bottleneck would be obliterated by subsequent linguistic diversification. This would have implications for our interpretation of the closeness of linkages between Tasmanian groups, since populations require isolation for linguistic diversification. I return to these points below. Downloaded from http://rspb.royalsocietypublishing.org/ on November 16, 2014 Tasmanian languages C. Bowern 4591 Given the paucity of island-wide research into genetic, archaeological and ethnographic diversity, language may provide us with the best opportunity of inferring change in prehistory. However, records of Tasmanian languages are poor [5,6]. The 44 known wordlists were recorded between 1777 and 1847. Vocabularies were recorded opportunistically, often with very little information about speakers or locations of recording. They vary in length from a single word to nearly 1040 items and originate from all over the island. In five cases, there is no information about provenance. Backhouse and Walker, for example, recorded vocabularies on Flinders Island from displaced persons of unknown tribal affiliation [5]. Other sources combined, or admixed, vocabulary from multiple locations, as evidenced both by the number of synonyms given in the lists and from comments from compilers. Other lists contain only general or ambiguous location information. Previous attempts [1,6,9] to discover the linguistic history of Tasmania are rife with equivocations and are internally irreconcilable, despite being based on identical source material. Roth [1] was convinced that there was a single language, despite quoting considerable ethnographic evidence to the contrary. Walker [20] follows Robinson in arguing for four languages, but does not provide any evidence for this conclusion. Schmidt [9] found two languages, one with three dialects; OGrady [7] also found at least two languages (but not the same two as Schmidt), while Crowley & Dixon [6] argued that source materials are too poor to (...truncated)