A. In November 1897, in a field near the village of Coligny in eastern France, a local inhabitant unearthed two strange objects. One was an imposing statue of Mars, the Roman god of war. The other was an ancient bronze tablet, 1.5 metres wide and 1 metre high. It bore numerals in Roman but the words were in Gaulish, a version of the Celtic language spoken by the inhabitants of France before the Roman conquest in the first century BC. The tablet turned out to be one of the most important sources of words from this extinct language.
B. Two researchers, geneticist Dr Peter Forster and linguist Dr Alfred Toth, have now used the calendar and other Celtic inscriptions to reconstruct the history of Celtic and its position in the Indo-European family of languages. They say that Celtic became a language in its own right and entered the British Isles much earlier than supposed. Then in the first century BC, the Romans defeated the Celts, both in France and in Britain, so decisively that their language, Latin, and its successor languages displaced Celtic over much of its former territory. In the British Isles, Celtic speakers survived in two main groups: the Goidelic branch of Celtic, which includes Irish and Scots Gaelic, and the Brythonic branch, formed mainly of Welsh and Breton, a Celtic tongue carried to Brittany in France by emigrants from Cornwall.
C. Because languages change so fast, historical linguists have little faith in language trees that go back more than a few thousand years. Dr Forster has developed a new dating method for relating a group of languages, basing it on the tree-drawing techniques used to trace the evolutionary relationships among genes. The method will work on just a handful of words, a fortunate circumstance since only some 30 Gaulish words have known counterparts in all the other languages under study. Dr Forster and Dr Toth have used the method to draw up a tree relating the different branches of Celtic to one another and to other Indo-European languages like English, French, Spanish, Latin and Greek. In a published article, they say that soon after the ancestral Indo-European language arrived in Europe over 5,000 years ago, it split into different branches leading to Celtic, Latin, Greek and English. Within Celtic, their tree shows that Gaulish, the mainland European version of the language, separated from its Goidelic and Brythonic cousins, much as might be expected from the facts of geography.
D. The researchers' method even dates the points at which their language tree divides, although the dates have a wide range of possibility. They calculate that the Indo-European language initially fragmented in Europe around 8100 BC, plus or minus 1,900 years, and the divergence between the mainland European and British versions of Gaelic took place in 3200 BC, plus or minus 1,500 years. These dates are much earlier than previously estimated. "The traditional date of the Indo-European fragmentation has been 4000 BC for some time," said linguist Dr Merritt Ruhlen. He said the new method "seems pretty reasonable" and should be useful in tracing back the earlier history of the Indo-European language.
E. Specialists have long debated which country was the homeland of the Indo-Europeans and whether their language was spread by conquest or because its speakers were the first agriculturists whose methods and tongue were adopted by other populations. The second theory, that it was spread by agriculture, has been advocated by archaeologist Dr Colin Renfrew. Dr Forster, who works with Dr Renfrew, said in an interview that the suggested date 8100 BC for the arrival of Indo-European in Europe does seem to vindicate Renfrew's archaeological idea that the Indo-European languages were spread by farmers. Agriculture started to arrive in Europe from the Near East around 6000 BC, which is earlier than the traditional date proposed by linguists for the spread of Indo-European. This writing would fit with the lower end of Dr Forster's range of dates.
F. Dr Forster said that his estimated date of 3200 BC for the arrival of Celtic speakers in the British Isles is also much earlier than the usual date, 600 BC, posited on the basis of archaeological evidence. Dr Forster and Dr Toth said their method of evaluating groups of languages against each other was similar to historical linguists, many of whom restrict their research to how words in only one single language have changed over time. Asked what linguists thought of his approach he said: "To be honest, they don't understand it, most of them. They don't even know what I'm talking about." The method used by Dr Forster and Dr Toth has two parts. One is to draw a tree on the basis of carefully chosen words; the second is to date the splits in the tree by calibrating them with known historical events. This is similar to the way geneticists date their evolutionary trees by tying one or more branch points to known dates from the fossil record.
G. Dr April McMahon, a linguist at the University of Sheffield in England, said that Dr Forster's method "seems to me to be a good start", and that it was reasonable to base a language family tree on just a handful of well-chosen words. She had less confidence in the dating method, she said, because language changes in an irregular way based on social factors like the size of the speaker's group and its degree of contact with others.