The first tentative steps towards the deliberate tending of food sources began with the close of the last Ice Age.

The new directions in subsistence did not begin in just one region of the world, but rather, between 11,000 and 5000 BCE, peoples in several different distant parts of the globe independently set these developments in motion.

To recover human history in those periods, historians typically rely on the findings of archaeologists. Less often scholars have marshalled a second set of tools, drawing on historical linguistics to advance the knowledge of those early times. Learning about these tools and how to use them is its own full course of study, and so only a short introduction to the key ideas is possible here.1

How far back in time can one carry the linguistic investigation of earlier human subsistence practices? That depends on how far back in time the currently available language family reconstructions extend. For some world regions scholars have constructed relatively deep-time linguistic histories. In Africa the linguistic record for the Nilo-Saharan, Niger-Congo, and Cushitic families extends back to the early Holocene era. In other regions of the world the existing reconstructions tend to be of more shallow time depth. Scholars working on the Austronesian language family, for example, and on the Oceanic branch of this family, can take their story back to the later middle Holocene in the island South Asia and Oceanic regions. The reach of the currently available linguistic evidence on early agriculture also extends back to the middle or the later middle Holocene for the Middle East, India, and Mesoamerica.

1 C. Ehret, ‘Linguistic archaeology', African Archaeological Review, 29/2 (2012), 109-30, provides a compact introduction. C. Ehret, History and the Testimony of Language (Berkeley: University of California Press, 2011), presents at greater length these methods and how they can be used in the reconstruction of human history, drawing particularly on African case studies.

The essential foundation for the linguistic recovery of history is a sys­tematic reconstruction of the relationships and phonological histories of the families of languages spoken in the regions whose human histories one wishes to investigate. Establishing the foundation is itself arduous and long-term work. But with the framework of language relationship in place, it becomes possible to systematically assess the evidence of language for history.

To say that a certain set of languages are related - that they belong to the same language family - means that they all descend from a single mother language, a protolanguage, spoken at some period in the past. Now, language descent is mitotic. Like a single-celled organism, a mother language diverges into daughter languages. It does not continue to be spoken alongside its daughters - it becomes its daughters. In subsequent eras the daughter lan­guages may in turn become mother languages, or protolanguages, by diver­ging into further daughters. A language diverges into daughter languages over a period of centuries through the gradual accumulation of new words and grammatical features and the loss of old; and unlike the usual outcome of mitosis in single-cell organisms, the protolanguage may undergo divergence into several daughters at once.

Through the application of historical linguistic methods, scholars can uncover the overall succession of divergences that took place in a family of languages over the millennia and, from these findings, construct a family tree of the relationships involved. The key to turning this family tree into a human historical framework is the fact that, in past ages, a language could exist only if there was a society that spoke it. If the community speaking a language lost the sense of separate ethnic identity and was incorporated over time into another society, their language would soon die out. If, in contrast, the communities who spoke a language began to lose their sense of belonging to a common society - for instance, because of divisive internal conflicts, or because some groups moved to new areas, distant from their fellow speakers - they might continue to speak the language.

A key contributor to language change over time is change in the lexicon - changes in the words used for particular things and actions, the addition of new words to the vocabulary, and the obsolescence and loss of other words. People need words for expressing all the aspects of their lives and knowl­edge, including the things and actions that comprise their economies. Whether they collect or cultivate plants, and whether they hunt or tend their meat sources, people must have the full lexicon necessary to commu­nicate about those activities and the features, ideas, and material items associated with them. To reconstruct the existence of an old root word for a particular activity or thing back to a particular node in the linguistic stratigraphy is to demonstrate that the society speaking the language at that point in time possessed the knowledge connoted by the word. They had or performed or, at the very least, knew of the thing or activity in question.

The presence in a protolanguage of a term for a specific crop or a specific domesticated animal, however, does not by itself demonstrate that the speakers of the protolanguage actually cultivated the crop or herded the animal. The reason is straightforward. Each food plant, once upon a time, before cultivation, would have been collected wild; each domestic animal once was wild. If a protolanguage was spoken within a plant's or an animal's region of origin, its reconstructed term for the plant or animal may well have originally designated the wild plant or animal. The essential diagnostic evidence in such a case would be verbs and nouns that specifi­cally connote or identify the activities of cultivation or herding.

Of course, if the protolanguage was spoken in a region distant from where the plant or animal existed in the wild, then the knowledge would have spread to the speakers of that language only because people somewhere else had already begun to cultivate the crop or tend the animal. In that case, one could argue that the speakers of the protolanguage were, at the least, neighbours of people who did cultivate the plant or raise the animal. But their possession of words specifically connoting cultivation or herding would still be important in showing conclusively that they themselves participated in those activities.

One other consideration, cultural salience, is also relevant to the historical intepretation of ancient lexicons. If an item had high salience in the culture of a past society, this circumstance can affect word histories in two ways. For one thing, when an item has high cultural salience, the word for the item tends to remain in use over very long periods; only infrequently will people adopt a new term for it.² A second indicator of high salience in earlier times can be the existence of a suite of reconstructed secondary words relating to or descriptive of the item. We will encounter examples of both kinds in our considerations here.

Nineteenth-century scholars first put into use the kinds of systematic method that scholars apply today in extracting history from language. The students of this field have since refined and expanded these approaches and applied them to some extent in every continent. In the past two and a half decades a revitalization of this field of scholarly endeavour has taken place, with the methods put to use not just in reconstructing material lifeways of past peoples, but in uncovering deep histories of change and persistence in such non-material areas of culture as political ideas,³ religious beliefs,⁴ gender relations,⁵ and kinship systems.⁶ The most extensive and detailed applications of language evidence have been in African history⁷ and

2 This feature is widely evident from studies in Africa.

3 NotablyJ. Vansina, Paths in the Rainforests (Madison: University of Wisconsin Press, 1990), and How Societies are Born (Charlottesville: University of Virginia Press, 2004); and D.L. Schoenbrun, A Green Place, A Good Place: Agrarian Change, Gender, and Social Identity in the Great Lakes Region to the 15th Century (Portsmouth, NH: Heinemann, 1998).

4 R.M. Gonzales, Societies, Religion, and History: Central-East Tanzanians and the World they Created, c. 200 bce to 1800 ce (New York: Columbia University Press, 2009).

5 C. Saidi, Women's Authority and SocietyinEarlyEast-CentralAfrica (University of Rochester Press, 2010).

6 E.g. P. McConvell, ‘Omaha skewing in Australia: overlays, dynamism, and change', in T. Troutmann and P. Whiteley (eds.), Crow-Omaha: New Light on a Classic Problem of Kinship Analysis (Tucson: University of Arizona Press, 2012), 243-60, among other works;

C. Ehret, ‘Reconstructing ancient kinship in Africa', in N.J. Allen et al. (eds.), Early Human Kinship: From Sex to Social Reproduction (Oxford: Blackwell, 2008), 200-31, and ‘Deep-time historical contexts of Crow and Omaha systems: perspectives from Africa', in Trautmann and Whiteley (eds.), Crow-Omaha, 173-202; P. Hage and J. Marck, ‘Proto-Bantu descent groups', and J. Marck and K. Bostoen, ‘Proto-Oceanic society (Austronesian) and proto­East Bantu society (Niger-Congo) residence, descent, and kin terms, c. 1000 bc', both in

D. Jones and B. Milicic (eds.), Kinship, Language, and Prehistory (Salt Lake City: University of Utah Press, 2011), 75-8, 83-94.

7 E.g. C. Ehret, Southern Nilotic History: Linguistic Approaches to the Study of the Past (Evanston, IL: Northwestern University Press, 1972), and An African Classical Age: Eastern and Southern Africa in World History, 1000 bc to ad 400 (Charlottesville: University of Virginia Press, 1998); J. Vansina, The Children of Woot: A History of the Kuba Peoples (Madison: University of Wisconsin Press, 1978), Paths in the Rainforests, and How Societies Are Born; Schoenbrun, A Green Place, A Good Place; K. Klieman, ‘The Pygmies Were Our Compass': Bantu and Batwa in the History of West Central Africa, Early Times to c. 1900 ce (Portsmouth, NH: Heinemann, 2003); R.M. Gonzales, Societies, Religion, and History; Saidi, Women's Authority; R. Stephens, A History of African Motherhood: The Case of Uganda, 700-1900 (Cambridge University Press, 2013).

in the history of the cultures and settlements of island South Asia and Oceania.^[71]