The acquisition of several word formation devices in American Sign Language (ASL) by deaf children learning ASL as a native language focused on some devices analogous to word formation devices in spoken languages (compounding, affixation, and derivation) and some in ASL that may not have counterparts in spoken languages. They were examined using two tests, one requiring the subjects to produce a new name for something given a verbal description of its function, and one calling for a new name for an invented item whose picture is provided. The tasks not only test the applicability of several proposed principles of the acquisition of word formation (semantic transparency, formal simplicity, productivity, and conventionality), but also reinforce the importance of using several tasks for revealing a variety of processes. Results indicate that specific tasks call for specific word formation processes to be used, and they are acquired following the principles of formal simplicity and semantic transparency. The results also suggest that tasks involving verbal description of stimuli call for word-based morphological devices while nonverbal pictural presentation of stimuli calls for word formation devices that are not word-based, at least for a visual language. (Author/MSE)