This wide-ranging study takes the story of Kenneth Jackson's "Language and History in Early Britain" on from the 12th century to the end of the 20th century, mainly by using written and oral recordings of place-names. The main emphasis is on the place-names of Cardiganshire (now Ceredigion) but place-names in other parts of Wales are also considered and they are all discussed in the context of historical dialectology. The author analyses the phonology of Cardiganshire place-names, in their spoken and written forms, particularly looking at changes in the period from the 18th to 20th centuries, although many features are shown to have their roots in earlier periods. His analysis of place-names provides the basis for a detailed discussion of the phonology of Cardiganshire dialects, in which the phonetic development of these dialects in the modern period is traced.