This study examines second language activation in Arabic-English bilinguals for whom Arabic was the first language. Modeling its design on Colome (2001), the research compared processing in a picture-phoneme matching task for Arabic-English bilinguals tested in the United States or in Saudi Arabia to determine whether activation of English differed in the two settings as predicted by Grosjean's (1982) language mode theory. Relying on a pragmatic worldview, an explanatory sequential mixed methods approach was adopted to gain a full perspective of the research problem. The results showed no differences in the activation of English for the two settings, but did indicate that both groups of participants experienced some interference of English. Overall, interference from English was observed in error rates, but not in response times. Correlational analyses revealed that individual differences in error rate in the English phoneme condition were predicted by the number of hours per week that participants used English. Individual differences in response time were predicted by the frequency of the English translation equivalent of the Arabic name of the picture. Finally, the study established the language processing mechanism of Arabic-English bilinguals as one in line with Grosjean's (1982) language mode theory, as Arabic-English bilinguals may be more likely to employ separate language strategies for sociocultural reasons than other types of bilinguals. [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.]