Lough is the name given to many lakes in the far north of England in the counties of Northumberland and Cumbria they are often located near the Whin Sill escarpment on which Hadrian's Wall runs. In northern England the word lough in this context is usually pronounced as 'loff'. This reflects the loss in modern standard English of the guttural 'ch' sound (as in Scottish 'loch') which in middle English was represented by 'gh' (as it still is in modern Hiberno-English and Ulster Scots).
