Deriving reversal in Old French nominal inflection

In this paper, we study Old French declension, a system which exhibits the theoretically challenging phenomenon of morphological reversal (Baerman, 2007). Furthermore, the declension system of Old French only recognises a single exponent -s, which marks different case/number combinations in different paradigms, contrasting with the unmarked form. We show that reversal is only one of several syncretism patterns found in the language and propose that Old French declension is best understood in terms of two systematic syncretisms: a natural split between singular and plural for feminines, and a Paninian split for masculines that systematically marks the objective plural. Reversal, and other seemingly morphomic splits arise as a result of idiosyncrasy in the NOM.SG cell, comprising inflection class-specific s-marking, as well as stem alternation and overabundance. We provide a formal analysis in terms of Information-based Morphology (Crysmann & Bonami, 2016) that effortlessly captures the systematic splits, as well as the variation in the nominative singular. We suggest that the high degree of idiosyncrasy in this cell paired with the reduced frequency of overt nominative NPs when compared to objective NPs may serve to explain why the system was actually quite short-lived.