Here, Melvyn visits Oswestry. Just five miles from the Welsh border, this is a frontier town whose name means "boundary". It's where Offa's Dyke and countless crumbling castles bear witness to centuries of shifting political allegiances. Language too, has been a battleground. Welsh and English have waxed and waned, woven and unravelled. Visit the town's bustling livestock market today and there is little Welsh to be heard. Centuries of relentless anglicisation, beginning in the Norman period, have rendered English the "lingua franca". Yet listen a little harder and more complex patterns emerge. There are Welsh idioms and words and Midlands' forms all jostling for position in the dialects of Shropshire.