This paper investigates phonological processes in the -l- ~ -an/un construction in Cebuano from two aspects: an Optimality-Theoretic perspective and a historical perspective. Initially reported by Wolff (1972), the -l- ~ -an/un construction involves infix -l- and suffix -an/un with an echo vowel after the infix -l-. In this paper, a dataset is established according to Yap and Bunye (1971) and Wolff (1972). In total, 59 roots are collected: 26 roots for simple affixation (-an/un) and 33 roots for complex affixation (-l- ~ -an/un construction). Different functions of affixes are also taken into consideration. The results suggest that stress in complex affixation tends to fall on the penultimate syllable, while stress in simple affixation tends to be on the final syllable in the outputs. According to the distributions in the dataset, four OT constraints in two rankings are proposed to account for the patterns of stress shift. Finally, this paper also discusses intervocalic -l- deletion from the aspect of sound change. It is found that -l-deletion has not yet swept the -l- in the -l- ~ -an/un construction in Cebuano.