This dissertation presents a new framework for the application of Vygotsky's Sociocultural Theory (SCT) in the second language (L2) classroom called Collaborative-Dynamic Assessment (C-DA). C-DA is a melding of Collaborative Learning (CL), Dynamic Assessment (DA), and Group Evaluation (GE) in all aspects of L2 instruction and assessment. A study was conducted with 64 university students in an intermediate Spanish classroom to determine if the application of C-DA would lower Foreign Language Classroom Anxiety (FLCA). Horwitz' (1986) Foreign Language Classroom Anxiety Scale (FLCAS) was administered to the participants at the beginning of the course and then again at the end of the course after the implementation of C-DA. Pair-wise t-tests were performed to measure any change in anxiety with the implementation of C-DA in the classroom. Of the 64 participants, 19 demonstrated a significant decrease in anxiety and 5 demonstrated a significant increase. Additionally, semi-structured interviews were conducted with focus-students selected from the sample to explore student perception of the implementation of C-DA. In addition to student perceptions of both negative and positive impacts of C-DA on FLCA, unfavorable interview responses included the lack of lectures, social and grouping concerns, inequity of grades and free loading, and a lack of time to complete work. The favorable responses included a feeling of solidarity between students, the impression that DA is a better indication of what students can do, an increase in learning, a positive response to help from the instructor, and a general feeling that all have something to offer. [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.]