This study examined the relationship between productive phonological knowledge and generalization learning patterns in phonologically disordered children. Nine functionally misarticulating children (ages 3:8-5:9) were trained on aspects of their phonological systems that were characterized as inventory constraints that constituted "least phonological knowledge" in relation to the adult sound system (Elbert & Gierut, 1986). The misarticulated sounds were trained in the context of consonant clusters. Although all the subjects exhibited equivalent levels of phonological knowledge on the same misarticulated sounds and identical training was provided, three different learning patterns were observed. Results are discussed with regard to the characterization of phonological knowledge in underlying representations that are depicted as "non-adult-like" or incorrect relative to the target sound system. Implications for clinical assessment are discussed.