ENGLISH and Indo-European words including 'I', 'we', 'two' and 'thou' have changed so little in tends of thousands of years that ancient hunter-gatherers would have been able to understand them. Researchers have also identified several words that could die out within 1,000 years because they are likely to evolve into different forms. They include "throw", "stick", "dirty", "guts" and "squeeze" which could all be out of use by the year 3000. Mark Pagel, of the University of Reading, who is leading the research, said that it was becoming possible to create a rudimentary 'time traveller's phrasebook' of words that could be understood by Stone Age cavemen. He told The Times: "If a time traveller wanted to go back in time to a specific date, we could probably draw up a little phrasebook of the modern words that are likely to have sounded similar back then. You wouldn't be able to discuss anything very complicated, but it might be enough to get you out of a tight spot." Other early words include 'two', 'three' and 'five'. Dr Pagel has tracked how words have changed by comparing languages from the Indo-European family, which includes most of the past and present languages of Europe, the Middle East and the Indian sub-continent. He has been able to track the evolutionary history of Indo-European back using a computer and said that some of the oldest words were well over 10,000 years old even though the original Indo-European language is thought to date back no more than 9,000 years. " DT "I can say with confidence that there are sounds or words that predate Indo-European," he said. "If you look at 'thou', 'I' and 'who', we can now tell they are probably at least 15,000 to 20,000 years old. The sounds used then for these meanings were probably very similar to those used today." Dr Pagel's work has shown that the pace at which words evolved depends on how they are used. Numerals are the slowest to change, followed by pronouns, probably because they are used extremely often and have a very precise and important meaning. Nouns evolve more slowly than verbs, and verbs evolve more slowly than adjectives. Words that are used less frequently evolve more quickly than those that are common. The oldest words, resistant to evolution I, Who, We, Thou, Two, Three and Five Words that are evolving rapidly, and likely to disappear Dirty, squeeze, bad, because, guts, push (verb), smell (verb), stab, stick (noun), turn (verb), wipe - Daily Telegraph