Alabama has a middle voice morpheme with three simple variants involving an l, which occur either as prefixes or infixes in the forms il, l, and li. The variants with l are in complementary distribution with a suffix -ka. The l variants of the middle echo a recurrent theme in Alabama verbal morphology whereby minimally specified phonological material is placed in various arrangements (C, VC, CV) and positions (prefix, infix, suffix) subject to certain general prosodic constraints on word formation or verb stem derivation. The formation of the middle voice stem is compared to that of negative stem formation and agent pronominal agreement and shown to be determined by the same general constraint: all radical morphological processes applying to verb stems in Alabama must result in a three-mora, two-syllable final foot. The l stem variants can be minimally specified as /1/ attached to a single mora. The appearance of a -ka suffix, which occurs rather than the phonologically expected*-li, is explained historically. The occurrence of a complex suffix -ilka is explained in terms of the semantics of the 'middle voice' affix and inherent 'middle' semantics of verb stems. © 1991.
Hardy, H. K., & Montler, T. (1991). The formation of the Alabama middle voice. Lingua, 85(1), 1–15. https://doi.org/10.1016/0024-3841(91)90042-4