He retains yod for Middle Chinese but has not ventured to publish an account of how his supposed Old Chinese short vowels could have spontaneously diphthongized
in this way.
Investigated by Trager (1930, 1934, 1940; see note 2), and discussed by Labov (1981, 1994) and Kiparsky (1988, 1996, and further references therein), since the Middle English period the low front lax vowel was long in certain contexts, and only in the most recent times is it being replaced by a raised and diphthongized
reflex in various eastern American locales.
The accents used by some newscasters on the BBC World Service (on which we expect RP to be used), however, sometimes have a rather fronted and slightly diphthongized /u:/ (as in through) and slight round ing on the nucleus of /ai/ (as in wide).
Similarly, the raised and diphthongized variant of short /a/ characteristic of conservative RP and described by Jones and Gimson has disappeared except in very old speakers and has been replaced by a low-vowel short variant, which is sometimes so retracted (especially in young women) that bad sounds like bud.
He correctly states that my first idea was that long vowels in Old Chinese had diphthongized
in Middle Chinese: *a:n[right arrow] *ien, etc.
The entire area under study has no long u because it has become diphthongized.
The overlong o is partly diphthongized in eastern Saaremaa.
In addition to the models that treat peripherality solely in terms of vowel quality, there are others in which both quality and quantity play an important part so that [+ peripheral] vowels are by and large long/ diphthongized
and "tense," and [-peripheral] vowels are short and "lax.
It has been called a "shift" because Luick thought the long vowel was bumped by [e:] and [0:] pushing from below, and having nowhere to go, it diphthongized
Quality change may also depend on quantity: overlong vowels may, for example, be diphthongized
, or, as in Voru dialect, raised.