This sociolinguistic study examines the functions and motivations of code-switching, which is used here to mean the use of more than one language in the same conversation. The conversations studied here take place in a very particular context: one-on-one speaking sessions in a study abroad program in Morocco where English is the L1 and Arabic the L2 of the students, and the opposite applies to their speaking partners. The conversations in this study are conducted in Arabic, and the study focuses on code-switching from Arabic to English in spite of whether the L1 of the speaker is Arabic or English. The functions of code-switching in this study are examined from the perspective of two well-known competing sociolinguistic approaches to code-switching: (1) the markedness model (Myers-Scotton, 1993, 1998; Myers-Scotton and Bolonyai, 2001), based on micro and macro-levels of analysis, and (2) the conversational code-switching approach (Auer, 1984, 1995, 1998; Li Wei 2002), based on micro-levels of analysis. Application of the markedness model showed that marked instances of code-switching were used for a variety of functions, such as (1) strengthening solidarity between speakers; (2) taking care of business and show seriousness and authority; (3) adding aesthetic effects; and (4) playing with words for the sake of joking. The model also showed that unmarked switches served different functions such as (1) requesting the meaning of vocabulary and expressions; (2) asking for accommodation (repetition and speaking slower); (3) bridging a communication gap; (4) and providing expressions and the meaning of vocabulary when circumlocution does not work. The conversational code-switching approach revealed the following functions of code-switching: (1) quotations and reported speech; (2) reiteration (for clarification); (3) change of participant constellation (selection of addressee); (4) language play; and (5) language negotiation. Both approaches proved effective in analyzing the Arabic-English data in this study. However, the analysis shows that the markedness model has an advantage over the conversational code-switching approach. The data shows evidence that speakers' choices are based on rationality rather than on sequential structure. Participants code-switch based on their own goals and what linguistic codes are available to them to achieve these goals. [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/en-US/products/dissertations/individuals.shtml.]