Chain Shift - Diachronic Shifts

Diachronic Shifts

A well-known chain shift in the history of English is the Great Vowel Shift of the 15th century, which can be summarized as follows:

(aː →) æː → eː → iː (→ əi) → ai and ɔː → oː → uː (→ əu) → au

A chain shift may affect only one regional dialect of a language, or it may begin in a particular regional dialect and then expand beyond the region in which it originated. A number of recent regional chain shifts have occurred in English. Perhaps the most well-known is the Northern Cities Vowel Shift, which is confined to the "Inland North" region of the United States. Other examples in North America are the California vowel shift, Southern vowel shift (in the Southern United States) and the Canadian Shift. In England, the Cockney vowel shift among working-class Londoners is familiar from its prominence in plays such as George Bernard Shaw's Pygmalion (and the related musical My Fair Lady):

iː → ei → ai → ɔi → oi

Many chain shifts are vowel shifts, because many sets of vowels are naturally arranged on a multi-value scale (e.g. vowel height or frontness). However, chain shifts can also occur in consonants. A famous example of such a shift is the well-known First Germanic Sound Shift or Grimm's Law, in which the Proto-Indo-European voiceless stop consonants became fricatives, the plain voiced stops became voiceless, and the breathy voiced stops became plain voiced:

bʱ → b → p → f

dʱ → d → t → θ

ɡʱ → ɡ → k → h,x

Another is the High German consonant shift which separated Old High German from other West Germanic dialects such as Old English, Old Frisian, and Old Saxon:

d → t → ts,s

(ɡ →) k → kx,x

(b →) p → pf,f

The Romance languages to the north and west of central Italy (e.g. French, Spanish, Portuguese, Catalan and various northern Italian languages) are known for a set of chain shifts collectively termed lenition, which affected stop consonants between vowels:

pp → p → b → β,v

tt → t → d → ð (or vanishes)

kk → k → ɡ → ɣ,j (or vanishes)

In this case, each sound became weaker (or more "lenited").