Language continuity despite population replacement in Remote Oceania

ancientdna-migrations-vanuatu

New article (behind paywall) Language continuity despite population replacement in Remote Oceania, by Posth et al., Nat. Ecol. Evol. (2018).

Abstract:

Recent genomic analyses show that the earliest peoples reaching Remote Oceania—associated with Austronesian-speaking Lapita culture—were almost completely East Asian, without detectable Papuan ancestry. However, Papuan-related genetic ancestry is found across present-day Pacific populations, indicating that peoples from Near Oceania have played a significant, but largely unknown, ancestral role. Here, new genome-wide data from 19 ancient South Pacific individuals provide direct evidence of a so-far undescribed Papuan expansion into Remote Oceania starting ~2,500 yr BP, far earlier than previously estimated and supporting a model from historical linguistics. New genome-wide data from 27 contemporary ni-Vanuatu demonstrate a subsequent and almost complete replacement of Lapita-Austronesian by Near Oceanian ancestry. Despite this massive demographic change, incoming Papuan languages did not replace Austronesian languages. Population replacement with language continuity is extremely rare—if not unprecedented—in human history. Our analyses show that rather than one large-scale event, the process was incremental and complex, with repeated migrations and sex-biased admixture with peoples from the Bismarck Archipelago.

So, despite the population replacement in Oceania seen recently in Genomics, the people of present-day Vanuatu continue to speak languages descended from those spoken by the initial Austronesian inhabitants, rather than any Papuan language of the incoming migrants.

Professor Gray, Director of the Department of Linguistic and Cultural Evolution at the MPI-SHH, says:

Population replacement with language continuity is extremely rare – if not unprecedented – in human history. The linguist Bob Blust has long argued for a model in which a separate Papuan expansion reaches Vanuatu soon after initial Austronesian settlement, with the initial, and likely undifferentiated, Austronesian language surviving as a lingua franca for diverse Papuan migrant groups.

Dr. Adam Powell, senior author of the study and also of the MPI-SHH, continues,

The demographic history suggested by our ancient DNA analyses provides really strong support for this historical linguistic model, with the early arrival and complex, incremental process of genetic replacement by people from the Bismarck Archipelago. This provides a compelling explanation for the continuity of Austronesian languages despite the almost complete replacement of the initial genetic ancestry of Vanuatu.

ancient-dna-migrations-oceania
Maps showing the migrations in the area, including, in the final map, the migrations revealed by the current study. Credit: Hans Sell, adapted from Skoglund et al. Genomic insights into the peopling of the Southwest Pacific. Nature (2016).

I think we can safely disagree now with their assertion. We are seeing more and more cases of language continuity in spite of population replacement quite clearly in Eurasian prehistory. At least:

All these cases can be explained with founder effects and gradual expansions after an initial arrival, maybe also initial close interaction between different ethnic groups, where one group (and its language) becomes the dominant one.

NOTE. Even if an alternative model is selected (say, that Corded Ware migrants spoke Indo-European languages), alternative language continuity events need to be proposed for some of these regions, so we are beyond their description as ‘rare language events’ already.

What is becoming clearer with ancient samples, therefore, is that there is little space for prehistoric cultural diffusion events (at least massive ones), which were quite popular explanations before the advent of genetic studies.

Related:

The over-simplistic “Kossinnian Model”: homogeneous peoples speaking a common language within clearly delimited cultures

proto-greek-mynian-ware

There seems to be a growing trend to over-simplistic assumptions in archaeology and linguistics, led by amateur and professional geneticists alike, due to the recent (only partially deserved) popularity of Human Evolutionary Biology.

These studies are offering ancient DNA samples, whose Y-DNA and mtDNA haplogroups and admixture analyses are showing some new valuable information on ancient cultures and peoples. However, their authors are constantly giving uninformed conclusions.

I have read a good, simple description of the Kossinnian model in the book Balkan Dialogues (Routledge, 2017), which has been shared to be fully read online by co-editor Maria Ivanova.

Chapter 3, The transitions between Neolithic and Early Bronze Age in Greece, and the “Indo-European problem”, by Jean-Paul Demoule, offers a clear account of the difficulties found in tracing the arrival of Proto-Greek speakers to Greece or the “Coming of the Greeks”. The identifications of cultural breaks most commonly supported by academics as potentially signaling the arrival of Proto-Greeks are cited, including the Early Helladic III period ca. 2300 BC (with the diffusion of Mynian ware), or the Middle Helladic period ca. 2000 BC. The problem of finding a clear cultural break before the emergence of Mycenaean Greece (which obviously spoke an early Greek dialect) has led some to adopt a “Palaeolithic autochthonous theory” (Giannopoulos 2012), which offers still more problems than it solves.

Of interest is his reference to Kossinna in light of the recent popularity in resorting to DNA to answer all problems. It is mandatory for the field of Indo-European studies – regardless of what renown labs and journals of high impact factor are publishing – to avoid carrying on “in the steps of race based cranial measurement which enjoyed its floruit in the 19th century before fading into oblivion.”

This is why, without denying the relationship between Indo-European languages, we need to question the validity of the overall model itself, which has shown itself to be over-simplistic in assuming the movement of permanent and long-lasting homogeneous “peoples”. More precisely, we have to criticize in details the “Kossinnian Model” underlying all those assumptions – “Kossinnian”, because of the German archaeologist Gustaf Kossinna (1858–1931), well known for the famous sentence: “Cultural provinces, which are clearly delimited on the basis of archaeology, correspond in every era to specific peoples or tribes” (“Scharf umgrenzte archäologische Kultur-provinzen decken sich zu allen Zeiten mit ganz bestimmten Völkern und Völkerstämmen”). Four basic assumptions arise from this central idea:

  1. Changes in languages are due to population movements, usually involving conquest, and every migration implies a linguistic change.
  2. Archaeological “cultures” are homogenous ethnic groups, with defined frontiers, based on the model of 19th- and 20th-century nation-states and equally on the model of biological entities that reproduce by parthenogenesis.
  3. There is coincidence between language and material culture.
  4. Finally, languages are also homogenous biological entities which are autonomous and clearly delimited, and which can reproduce by parthenogenesis or by scissiparity.

Unfortunately, none of these points is self-evident and each can be countered by a number of historical examples (Demoule 2014: 553–592).

While I agree with the first part of the first statement attributed to the “Kossinnian model”, i.e. that languages are usually the product of population movements (either involving conquest or not), the other statements are obviously and demonstrably false, and are frequently assumed in comments, blog posts, forums, and even research articles – particularly in those based on genetic studies -, and this trend seems to be increasing lately.