Diminutive derivations (e.g., froggy, bootie) constitute morphophonologically similar clusters of words in child-directed speech and serve as low-level schema for learning morphological regularities. Previous research has demonstrated that by regularizing noun endings, diminutives (e.g., Russian: domik, svechka) facilitate word-boundary identification and the acquisition of inflectional morphology. In this study, adult native speakers of English (N = 77) were exposed to diminutive and simplex transparently gender-marked nouns instantiating Russian case-marking and adjective-noun gender- agreement patterns, over six 1-hour language-learning sessions. They were subsequently tested on their ability to extend grammatical patterns to new items and vocabulary recall. Learners showed equivalent learning of the trained phrases containing diminutive and simplex nouns but were more accurate in generalizing morphological patterns to diminutive nouns. Furthermore, learners showed a diminutive advantage in vocabulary retention. By increasing the invariant parts of words, diminutive derivations may reduce the amount of phonological material to be memorized and, subsequently, enhance word learning.