The paper reports the results of a learnability experiment with German speakers, investigating the role of universal phonotactic constraints and language use in language processing. Making use of an artificial language paradigm, participants learned nonce words with existent and non-existent German final consonant clusters adhering to or violating sonority sequencing principles postulated for consonant clusters. Behavioural data and event-related brain potentials in response to these cluster properties were obtained twice, before and after learning word-picture-pairs. The results show (1) that learning and processing of final consonant clusters is facilitated by adherence to the sonority hierarchy, and (2) that actual existence of well- and ill-formed consonant clusters aids processing mechanisms. Thus, both implicit knowledge of universal phonotactic principles and frequency-based factors are demonstrated to play a role in the online-processing of words.