Despite the importance that learners must place on using prosody appropriately in EIL interaction, pragmatic functions of prosody have been largely disregarded in teaching materials and classroom instruction (Nikolic, 2018). Moreover, with a recent change in classroom paradigms instigated by the global development of educational technologies and reinforced by the recent pandemic, there is an increased need for pragmatic instruction that can be delivered to learners digitally and remotely (Taguchi, 2011b). Although distance learning has played an important role in English teaching and learning long before the pandemic, its impact is even more meaningful today, when English learners all over the world are still experiencing difficulties related to in-person instructional access. The current mixed-methods quasi-experimental dissertation study investigated the extent to which English learners' interaction skills can improve as a result of contextualized prosody instruction on a web-based platform. Seventy-four English learners from China were randomly assigned to a two-week program that consisted of explicit pragma-prosodic instruction as well as perception-and production-based exercises. Learners' use of prosody in requests before and after instruction was recorded through video-based role plays, analyzed acoustically, and evaluated for appropriateness, accentedness, and comprehensibility by 20 trained raters. In order to provide a complete picture of instructional effectiveness, the study accounted for variation in learners' aptitude for acquiring prosodic properties of English by measuring their working memory, musical sensitivity, and auditory processing skills. The study results demonstrated significant changes in learners' use of pragma-prosodic features of interaction after the training; however, these changes did not have an effect on listeners' appropriateness perceptions, highlighting the complex nature of this construct that requires further clarification. At the same time, a significant albeit weak relationship was detected among listeners' perceptions of accentedness, comprehensibility, and appropriateness. Finally, the results revealed that learners' musical sensitivity, working memory as well as tone choice and prominence discrimination ability affected the success of the training in improving their use of pragma-prosodic features from the acoustic perspective. These findings provide important guidance for designing digitally mediated contextualized prosody instruction and help to better understand the role of learners' aptitude in its effectiveness. [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.]