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                                The dominant language in Britain from 1000 BC through  the military occupation of the Romans. Oddly, it has had minimal impact upon Modern English.  Only a dozen or so words such as ... whiskey, plaid, galore, crag, penguin, and shamrock... remain in Modern English from this tongue.  But, it had been spoken throughout all of the British Isles for over a millenium.    
                                What is Celtic?