The study explores factors that enhance or inhibit the language adjustment of international students in the U.S. Using social network influence model, the study examines the effects of language resources, language norm, and technology use on international students' self-confidence in overall English skills and four subskills, namely, listening, speaking, reading, and writing. The social network analysis is conducted on longitudinal data collected via two surveys administered to eighty one international students enrolled in the English Learning Center at a midwestern university. The findings suggest a number of variables boosting English confidence of international students: usage of mass media related to host community, usage of technology to contact family (in home country), the size of one's personal network, the proportion of English speakers (both native and non-native) in one's personal network weighted by the contact frequency. Meanwhile, this study disproved a set of variables suggested by the literature that is beneficial to language adjustment: length of residence (in the US), the percentage of native English speakers in the participants' social networks, and home country-related mass media usage. Length of residence in the US had no significant impact on English self-confidence, indicating that living in the US for longer period of time does not automatically improve one's confidence in using English. The study found that the participants' English confidence benefits from a larger personal network consisting of both non-native and native speakers, instead of native English speakers only. Implications for institutional policy and future research are discussed. [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.]