In phonology, a chain shift is a phenomenon in which several sounds move stepwise along a phonetic scale. The sounds involved in a chain shift can be ordered into a "chain" in such a way that, after the change is complete, each phoneme ends up sounding like what the phoneme before it in the chain sounded like before the change. The rules making up a chain shift are said to be in counterfeeding order.
For example, if in some language the three vowel phonemes /æ ɛ e/ undergo a change such that /e/ becomes /i/, /ɛ/ becomes /e/, and /æ/ becomes /ɛ/, those three changes would constitute a chain shift and could be summarized as
A pull chain is a chain shift in which the phoneme at the "leading" edge of the chain changes first. In this example, the chain shift would be a pull chain if /e/ changed to /i/ first, opening up a space at the position of [e] which /ɛ/ 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 /æ/ moved toward [ɛ], creating a "crowding" effect and causing /ɛ/ to move toward [e], and so forth.
Contents |
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:
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):
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 such as Old English, Old Frisian, and Old Saxon:
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:
In this case, each sound became weaker (or more "lenited").
It is also possible for chain shifts to occur synchronically, within the phonology of a language as it exists at a single point in time.
Nzebi (or Njebi), a Bantu language of Gabon, has the following chain shift, triggered morphophonologically by certain tense/aspect suffixes:
| a | → | ɛ | → | e | → | i |
| ə | → | i | ||||
| ɔ | → | o | → | u |
Examples (Guthrie 1968) follow:
| Underlying form | Chain-shifted form |
|---|---|
| sal "to work" | sal-i → sɛli |
| βɛɛd "to give" | βɛɛd-i → βeedi |
| bet "to carry" | bet-i → biti |
| bis "to refuse" | bis-i → bisi |
| kolən "to go down" | kolən-i → kulini |
| tɔɔd "to arrive" | tɔɔd-i → toodi |
| suɛm "to hide oneself" | suɛm-i → suemi |
Another example of a chain from Bedouin Hijazi Arabic involves vowel raising and deletion:
| a | → | i | → | deletion |
In nonfinal open syllables, /a/ raises to /i/ while /i/ in the same position is deleted.
Synchronic chain shifts may be circular. An example of this is Xiamen tone or Taiwanese tone sandhi:
| 53 | → | 44 | → | 22 | → | 21 | → | 53 |
The contour tones are lowered to a lower tone, and the lowest tone (21) circles back to the highest tone (53).
Synchronic chain shifts are an example of the theoretical problem of phonological opacity. Although easily accounted for in a derivational rule-based phonology, its analysis in standard parallel Optimality Theory is problematic.