The main purpose of this paper is to present data about schm constructions in English and to examine them within the framework of Optimality Theory. American people sometimes reduplicate a word in deprecation using a prefix schm- or shm-, as in fancy-shmancy, and old-shmold. In these data, reduplicants surface as a copy of the whole word except the onset of the first syllable, which is replaced with schm. My data include some examples where the onset of the second syllable, not the first syllable, within the word reduplication is deleted and replaced with fixed segmentism schm, which seems to be infix rather than prefix. Above all, this study presents concrete evidence for the existence and function of ‘syllable’ and ‘foot’ known as prosodic categories by examining schm reduplication. Such extensions of schm-reduplcation also make predictions about types of outputs corresponding to their inputs.