Some philologists (e.g. Förster, in Der Flussname Thenisc) now hold that the English process belonged to the seventh century and was not completed till the beginning of the eighth; it thus belonged wholly to Britain and did not begin until after the completion of the first stage of British i-affection (the 'final i-affection'). But no linguistic matters are simple in this region. The beginnings of the process in English must lie back in pre-invasion times, whatever may be true of its results, or of any of its vocalic effects sufficient to be recognized in spellings. For this process is not peculiar to the English dialect of Germanic, transferred from its native soil west to Celtic Britain. Indeed the native soil of English seems to have been a focus of this phonetic disturbance (in its inception one primarily affecting consonants). Northwards it is found attacking the Scandinavian dialects with almost equal severity; though southwards its effects were more limited or later. Certainly moving west, within the area of the disturbance, the process was not retarded in English – what would have happened if it had moved southwards is another matter – and in the event English became the language of i-mutation par excellence and its results were far more extensive than in any form of British. In British, for instance, long vowels were not affected; but in English nearly all long vowels and diphthongs were mutated.
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