Many language training software packages are intended for self-study and marketed as complete language learning solutions; however, little is known about how well they work or under what conditions they should be used. This article reports on a research study conducted at the University of Maryland Center for Advanced Study of Language that explores the way adult learners use Rosetta Stone and Auralog's TELL ME MORE--two popular, commercially available, technology-mediated self-study packages. Volunteers from different United States government agencies agreed to use these programs according to each manufacturer's usage guidelines and to complete regular assessments to document their language proficiency throughout the study. The most striking finding was severe participant attrition, which was likely due to a variety of technological problems as well as the lack of sufficient support for autonomous learning in the workplace. This lack of compliance with self-study suggests that despite the logistical ease of providing language learning software, more resource-intensive types of language training are more likely to be effective. (Contains 5 tables, 4 figures, and 9 notes.)