For example, some speakers in Scotland still pronounce house similarly to its sound in Middle English before the shift, as [hu(ː)s].
Perhaps the most well-known is the Northern Cities Vowel Shift, which is largely confined to the "Inland North" region of the United States.
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:[citation needed] In this case, each sound became weaker (or more "lenited").
[5] Nzebi (or Njebi), a Bantu language of Gabon, has the following chain shift, triggered morphophonologically by certain tense/aspect suffixes: Examples follow:[6] Another example of a chain from Bedouin Hijazi Arabic involves vowel raising and deletion:[5] In nonfinal open syllables, /a/ raises to /i/ while /i/ in the same position is deleted.
Although easily accounted for in a derivational rule-based phonology, its analysis in standard parallel Optimality Theory is problematic.