Abstract. The Multiple Input approach in Optimality Theory for Korean allomorph alternations has been challenged by recent research. It is shown not only to have failed in dealing with alternations after ŋ-final stems and with the lo/ilo and the wa/kwa
alternations, but also to have resulted in a ranking paradox between different allomorph sets. These problems lead researchers to argue that Optimality Theory is incapable of dealing with the Korean allomorphy or to propose a separate selection device outside of the evaluation component to
explain the allomorph alternations in Korean. This paper, however, shows that the apparent problems come from the partially optimizing nature of Korean noun allomorphy. It argues that parallel evaluation with multiple inputs has no problem in dealing with Korean allomorphy. A universal allomorphy
constraint, DEFAULT ALLOMORPH, which prefers a phonologically simple allomorph, is proposed to remedy the problems found in the previous analyses. With DEFAULT ALLOMORPH and other relevant constraints, we do not have to resort to separate selection/elimination stages or to language-particular
and morpheme-specific constraints to explain Korean noun particle allomorph alternations.