An exercise in the evaluation of errors in Spanish (second language) composition is reported. The exercise, based on J. M. Hendrickson's "discovery" approach to learning, concerned correction of three error types: lexicon; grammar; and spelling. Subjects were 13 native English-speaking university students in a Spanish language program. In the first draft of a film review, the teacher provided feedback on the presence and location of errors but did not provide correct forms; the students were then responsible for finding the source of error and correcting it. The teacher subsequently built a profile of linguistic errors made by individual students and by the majority of the class, which is presented and discussed here. The exercise has as its objectives to help students correct errors in future compositions and to support classroom discussion of errors. Contains seven references. (MSE)