West New Guinea
Nuclear New Guinea
Northeast New Guinea
East New Guinea
Indo-Pacific is a hypothetical language macrofamily proposed in 1971 by Joseph Greenberg. Supporters see it as an extremely ancient and internally diverse family. It would group into a single language family the Papuan languages of New Guinea and Melanesia, and also includes the languages of the Andaman Islands and the languages of Tasmania, both of which are remote from New Guinea. Greenberg explicitly excludes from Indo-Pacific the languages of Australia. The hypothesis has not been accepted, since it was based on rough estimation of lexical similarity and typological similarity. New Guinea is often seen as a case of extreme diversity of language lineages by worldwide standards. Stephen Wurm's Trans–New Guinea languages family is a more widely entertained proposal.
The Indo-Pacific proposal, grouping the non-Austronesian languages of New Guinea with certain languages spoken on islands to the east and west of New Guinea, was first made by Greenberg in 1971. Greenberg's supporter Merritt Ruhlen considers Indo-Pacific an extremely diverse and ancient family, far older than Austronesian, which reflects a migration from southeast Asia that began only 6 000 years ago; he notes that New Guinea was inhabited by modern humans at least 40 000 years ago, and possibly 10 000 to 15 000 years earlier than that. Luigi Luca Cavalli-Sforza sees Indo-Pacific as a very heterogenous family of 700 languages and suggests that it may be more than 40 000 years old.
Ruhlen has attempted to broadly outline the history of the migrations that he believes produced Indo-Pacific and the world's other language families. Modern humans would have had a homeland in Africa. Shortly after 100 0000 BP (before the present) a group of modern humans migrated out of Africa, spreading first to the Near East, then beyond to Southeast Asia and Oceania. The first of these migrations separated sub-Saharan Africans from all other humans, while the second led to the populations of Southeast Asia, New Guinea, and Australia. The Indo-Pacific family, like the indigenous Australian languages, would have had its origins in the second of these two early divisions in the human family tree.
Greenberg's proposal was based on rough estimation of lexical similarity and typological similarity and has not reached a stage where it can be confirmed by the standard comparative method, including the reconstruction of a protolanguage. The greatest controversy concerns the geographic outliers, Andamanese and Tasmanian. The Ongan languages may form part of a family with Austronesian, and thus not be part of Indo-Pacific (Blevins, 2007). The languages of Tasmania are extinct and so poorly attested that many historical linguists regard them as unclassifiable. Roger Blench has dismissed the Indo-Pacific proposal as improbable, observing that while it "purported to be a purely linguistic exercise...it conveniently swept up all the languages of the crinklyhaired populations in the region that were not clearly Austronesian." He writes that despite decades of further research into Papuan languages and prehistory, Indo-Pacific still has "almost no assent from specialists in the field" and that it "only exists in the eye of the believer."
Since Greenberg's work, the languages of New Guinea have been intensively studied by Stephen Wurm. Wurm's Trans–New Guinea languages family includes about 70 percent of the languages Greenberg included in Indo-Pacific, though the internal classification is entirely different. Wurm states that the lexical similarities between Great Andamanese and the West Papuan (which is not part of Trans–New Guinea) and certain languages of Timor "are quite striking and amount to virtual formal identity […] in a number of instances", but considers this to be due to a linguistic substratum rather than a direct relationship.
External classification 
Merritt Ruhlen comments that, "At the present time the evidence connecting Indo-Pacific to the world's other language families is sparse, comparable perhaps to the relatively weak links between Khoisan and other families", but adds that "...there do appear to be some threads connecting Indo-Pacific with the world's other language families, threads that further research can be expected to strengthen." He sees this lack of evidence as the result partly of our general lack of knowledge of these languages and the almost complete lack of meaningful historical studies of them, and partly of the great linguistic diversity of New Guinea. Ruhlen gives the Southern Tasmanian mo-took (forefinger), the Southeastern Tasmanian togue (hand), the Proto-Karonan *dik (one), the Boven Mbian tek (fingernail), and the Digul tuk (fingernail) as examples of forms that may be related to tik, a widespread root "whose original meaning was probably 'finger'." According to him, the root can also be found in Nilo-Saharan, Niger–Kordofanian, Afroasiatic, Eurasiatic, Dené–Caucasian, Austric, and Amerind.
Ruhlen regards pal, meaning two, as another common root in the world's languages; within Indo-Pacific, related forms with the same meaning in the Andamanese languages include Biada's (ik)pāūr(-da), Kede's (ír-)pōl, Chariar's (nér-)pól, and Juwoi's (ró-)pāūr, related forms with the same meaning in Tasmania include Southeastern Tasmanian's boula ~ bura and Southern Tasmanian's pooalih, and related forms with the same meaning in New Guinea include Ndani's bere and Sauweri's pere. According to him, similar forms can also be found outside Indo-Pacific in Australian, Nilo-Saharan, Niger–Kordofanian, Afroasiatic, Eurasiatic, Dravidian, Austric, and Amerind, although its meaning has changed significantly in some of these families.
According to Greenberg, Indo-Pacific consists of fourteen families. He suggested a tentative sub-classification into seven groups, listed in bold below.
- Nuclear New Guinea
- West Papuan
- East New Guinea
- Northeast New Guinea
This classification was never widely accepted, and has largely been supplanted by that of Stephen Wurm. They do not generally agree well. For example:
- Greenberg's North New Guinea family corresponds to four of Wurm's families, Sko, Sepik–Ramu, Torricelli, and the Northern branch of Trans–New Guinea;
- Greenberg's West New Guinea family corresponds to four of Wurm's, East Bird's Head, Geelvink Bay, the South Bird's Head and West Bomberai branches of Trans–New Guinea, and the Bird's Head branch of West Papuan.
The few similarities are retentions from earlier linguists' work:
- Greenberg's Northeast New Guinea family closely matches Wurm's Madang-Adelbert Range branch of Trans–New Guinea
- Greenberg's Eastern New Guinea family and Wurm's Eastern Main-Section branch of Trans–New Guinea both preserve Tom Dutton's Southeast New Guinea family.
- Ruhlen, Merritt. The Origin of Language: Tracing the Evolution of the Mother Tongue. John Wiley & Sons, Inc: New York, 1994
- Cavalli-Sforza, Luigi Luca. Genes, Peoples, and Languages. University of California Press: Berkeley, 2001
- Wurm, S.A. (1977). New Guinea Area Languages and Language Study, Volume 1: Papuan Languages and the New Guinea Linguistic Scene. Pacific Linguistics, Research School of Pacific and Asian Studies, Australian National University, Canberra.
- Greenberg, Joseph H. 1971. "The Indo-Pacific hypothesis." In Current Trends in Linguistics, Vol. 8: Linguistics in Oceania, edited by Thomas A. Sebeok, 808-71. The Hague: Mouton. (Reprinted in Greenberg, Genetic Linguistics, 2005, 193-275.)
- Greenberg, Joseph H. 2005. Genetic Linguistics: Essays on Theory and Method, edited by William Croft. Oxford: Oxford University Press.
- O'Grady, Dobrovolsky, Katamba. 1997. Contemporary Linguistics.
- Usher, Timothy. "A comparison of Greenberg's and Wurm's classifications." In Greenberg, Genetic Linguistics, 2005, 261-269. (Systematic tabulation of the two sets of results.)
- Wurm, Stephen A. 1982. The Papuan Languages of Oceania. Tübingen: Gunter Narr.