The emergence of morphological patterns from lexical storage in language acquisition is conditioned by language-specific factors as well as extra-linguistic cognitive capacities. With particular reference to the acquisition of plural markers in German, in a memory-based perspective highlighting interesting theoretical implications for usage-based models, the paper analyses acquisitional strategies by focussing on emergent relations between stored word forms and on dynamic expectation/competition of incoming input. In particular, we outline an adaptive multifactorial account of morphological processing that includes both frequency and formal factors. Our investigation is supported by a computational model of morphology acquisition/processing based on self-organisation memories, where word representations are dynamically recoded as time-series.