Going the Distance: Synchronic Chain Shifts in Optimality Theory

Synchronic chain shifts, whereby certain sounds are promoted (or demoted) stepwise along some phonetic scale in some context, are one of the classic cases of opaque rule interactions (see, e.g., Kenstowicz and Kisseberth 1977). If, for example, /a/ raises to [e], and /e/ raises to [i], it would appear that the /e/ ® [i] raising must precede /a/ ® [e] raising in the derivation, otherwise /a/ and /e/ would both neutralize to [i].1 These cases therefore pose a challenge for non-derivational theories of phonology, including standard (strongly parallel) Optimality Theory (henceforth OT).2 McCarthy (1993) and Orgun (1995) have given OT analyses of a particular chain shift, namely a®i® ̄ reduction in Hijazi Bedouin Arabic; however, both these solutions are limited to chain shifts which involve no more than two Òlinks,Ó where one of the links involves deletion. I examine synchronic vowel raising alternations in Basque (Kenstowicz and Kisseberth 1979, Hualde 1991) and Nzebi (Guthrie 1968). Neither of these chain shifts involves deletion; and the Nzebi case involves a three-link chain shift. Employing the notion of distantial faithfulness, i.e. minimization of distance between underlying and surface values along the phonetic scale, I show that an OT analysis is not only capable of handling these sorts of alternations, but is the only approach which can formally characterize such shifts in a unified manner. Constraints enforcing distantial faithfulness can in turn be derived from ordinary featural faithfulness constraints by the operation of local conjunction (Green 1993, Smolensky 1995). Let us begin with the previous treatments of vowel reduction in the H ¢arb dialect of Bedouin Hijazi Arabic (BHA) (Al-Mozainy 1981). In non-final open syllables, short /a/ raises to a high vowel (transcribed [i], realized as [i], [u], or [ ] depending on adjacent consonants), while short /i/ syncopates (short /u/ is marginal, and in any case behaves like /i/):