LOL. Oh dear, coming from south of Watford, I think I'd better extend apologies! Got that one from the hatless part of the clue, I'm afraid, not from any geological expertise.
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I think sometimes (oh yes I do!) that it's a pity we don't know more about Scottish, Welsh, Cornish and Irish languages. We are taught one or more of French, German, Spanish, Italian etc at school, which is great. Latin too is a great help in understanding English, which sounds a bit of a contradiction..
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I'm not sure one can just 'pick up' these languages and dialects: I bought a Cornish grammar while on holiday, to study while on the beach, and I'm afraid the complexities of the language defeated me. Hope Didymus isn't reading this ...