The reflexes of the British diphthong au

The paper revisits the question of the way the British diphthong *au is reflected in the extant Brittonic languages. The proposal that the correct chain of development was *au > *ō > W u is upheld, the evidence for the alternative proposal, *au > * ō̧ > tonic MW aw, being examined and found inadequate. Related issues of the origins of some forms of the conjugated prepositions, some etymologies and some further contingent matters are discussed.