A quantitative research study was conducted to understand the extent to which gamification (i.e., game elements and mechanics) impact adult learners' satisfaction (in terms of app usability), perception, motivation and knowledge when they interact with a gamified mobile app on Spanish-as-a-foreign language learning. An online experimental study was conducted with 200 volunteers who were given pre-designed apps for the learning and practice of Spanish verb patterns. The experimental group used a gamified version of the app that included nine distinct game elements and mechanics. Participants were asked to provide feedback on the usability of the app by completing a satisfaction survey that measures effectiveness, efficiency and satisfaction; an intrinsic motivation inventory (in six categories); a perception questionnaire on nine game elements--aesthetics, competition, time, reward structures, feedback, levels, storytelling, resources and chance; and knowledge acquisition tests. Welch's "t"-tests and several simple linear regressions were run. Gamification of a Spanish-as-a-foreign language learning app has an effect on adult learners' satisfaction and motivation specially when it comes to perceived competence and effort or importance. The study shows demonstrates no evidence of a relationship between adult learners' perceptions of the usefulness of game elements and usability (effectiveness, efficiency and satisfaction), motivation and knowledge, except in specific instances. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]