Chain shift

A well-known example is the Great Vowel Shift, which was a chain shift that affected all of the long vowels in Middle English. The changes to the front vowels may be summarized as follows:

→ → →

A drag chain or pull chain is a chain shift in which the phoneme at the "leading" edge of the chain changes first. In the example above, the chain shift would be a pull chain if changed to first, opening up a space at the position of , which then moved to fill. A push chain is a chain shift in which the phoneme at the "end" of the chain moves first: in this example, if moved toward , a "crowding" effect would be created and would thus move toward , and so forth. It is not known which phonemes changed first during the Great Vowel Shift; many scholars believe the high vowels such as started the shift, but some suggest that the low vowels, such as , may have shifted first.

Examples

During the Great Vowel Shift in the 15th and 16th centuries, all of the long vowels of Middle English, which correspond to tense vowels in Modern English, shifted pronunciation. The changes can be summarized as follows:

Most vowels shifted to a higher place of articulation, so that the pronunciation of geese changed from to and broken from to . The high vowels and became diphthongs (for example, mice changed from to ), and the low back vowel was fronted, causing name to change from to .

The Great Vowel Shift occurred over centuries, and not all varieties of English were affected in the same ways. For example, some speakers in Scotland still pronounce house similarly to its sound in Middle English before the shift, as .

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 largely confined to the "Inland North" region of the United States. Other examples in North America are the Pittsburgh Vowel Shift, the Southern Vowel Shift (in the Southern United States), and the Low-Back-Merger 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):

→ → → →

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:

→ → →

→ → →

→ → →

Another is the High German consonant shift which separated Old High German from other West Germanic dialects (namely Old English, Old Frisian, Old Saxon, and Old Low Franconian).

Note that the rightmost development in the table is the oldest (drag chain). The degrees to which High German dialects have completed these changes vary vastly (see Rhenish fan).

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:

→ → → ,

→ → → (or vanishes)

→ → → , (or vanishes)

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