Edward Sapir (18841939). Language: An Introduction to the Study of Speech. 1921.
ou to au; German ü to öü to oi). These dialectic parallels cannot be accidental. They are rooted in a common, pre-dialectic drift.
Phonetic changes are regular. All but one (English table, X.), and that as yet uncompleted, of the particular phonetic laws represented in our tables affect all examples of the sound in question or, if the phonetic change is conditional, all examples of the same sound that are analogously circumstanced.14 An example of the first type of change is the passage in English of all old long i-vowels to diphthongal ai via ei. The passage could hardly have been sudden or automatic, but it was rapid enough to prevent an irregularity of development due to cross drifts. The second type of change is illustrated in the development of Anglo-Saxon long o to long e, via ö, under the influence of a following i. In the first case we may say that au mechanically replaced long u, in the second that the old long o split into two soundslong o, eventually u, and long e, eventually i. The former type of change did no violence to the old phonetic pattern, the formal distribution of sounds into groups; the latter type rearranged the pattern somewhat. If neither of the two sounds into which an old one splits is a new sound, it means that there has been a phonetic leveling, that two groups of words, each with a distinct sound or sound combination, have fallen together into one group. This kind of leveling is quite frequent in the history of language. In English, for
Note 14. In practice phonetic laws have their exceptions, but more intensive study almost invariably shows that these exceptions are more apparent than real. They are generally due to the disturbing influence of morphological groupings or to special psychological reasons which inhibit the normal progress of the phonetic drift. It is remarkable with how few exceptions one need operate in linguistic history, aside from analogical leveling (morphological replacement). [back]