Derivative Word Forms: What Do Learners Know?

Some teachers and researchers may assume that when a learner knows one member of a word family (e.g., stimulate), the other members (e.g., stimulant, stimulative) are relatively easy to learn. Although knowing one member of a word family undoubtedly facilitates receptive mastery of the other members, the small amount of previous research has sug-gested that L2 learners often have problems producing the various derivative forms within a word family. This study examined the ability of 106 graduate and undergraduate nonnative-English-speaking students to produce appropriate derivatives in the four major word classes (i.e., noun, verb, adjective, and adverb) for 16 prompt words. The results indicated that it was relatively uncommon for subjects to know either all of the four word forms or none of them. Subjects usually had partial knowledge of the derivatives, with productive knowledge of two or three forms being typical. In a comparison of derivational mastery and knowledge of the prompt words on a four-stage developmental scale,