Abstract
This study applies Stratal Optimality Theory (OT) to illuminate the phonological opacity of local Compensatory Lengthening (CL) in Modern Colloquial Persian, which targets moraic glottal consonants /h/ and /?/ in the postvocalic position. It concludes that moraic structure is built before segmental changes through Weight-by-Position (WBP), which applies before consonant deletion or vowel lengthening. This order of application ensures that moras are assigned to coda consonants before their deletion to facilitate the affiliation offloating moras to preceding stem vowels. This opaque phonological derivation involves consonant deletion counterbleeding WBP. Unlike Standard OT, Strata' OT is shown to be capable of accounting for counterbleeding through strata with different sets of OT constraints; the first stratum guarantees building moraic structure prior to segment deletion or lengthening, while the secBond stratum guarantees counterbleeding to account for CL.