Isca Dumnoniorum but seems to have gone into decline prior to the Roman withdrawal from Britain . The name "Isca Dumnoniorum" is a Latinization of a native Brittonic name describing flowing water, in reference to the River Exe. More exactly, the name seems to have originally meant "full of fish" (cf. Welsh "pysg", "fish"), although it came to be a simple synonym for water (cf. Scottish whiskey). This is also reflected in the modern Welsh name for Exeter: "Caerwysg" meaning "fortified settlement on the river Uisc". The same name was used for the River Usk (modern ) in southern Wales, causing the
Celtic language decline in England a "vicus", and others end in elements denoting Roman features, such as "-caster", denoting "castra" ('forts'). There is a substantial body of names along the lines of "Walton"/"Walcot"/"Walsall"/"Walsden", many of which must include the Old English word "wealh" in the sense 'Celtic-speaker', and "Comberton", many of which must include Old English "Cumbre" 'Britons'. These are likely to have been names for enclaves of Brittonic-speakers─but again are not that numerous. In the last decade, however, scholars have stressed that Welsh and Cornish place-names from the Roman period seem no more likely to survive than Roman names in England: 'clearly name loss