In Taiwan, high school students' learning trajectory is mainly conditioned by the high-stakes examinations for college admission. However, upon entering college, they must adjust their mindset and develop self-directed learning skills to manage the enormous amount of specialized content and demonstrate their knowledge through writing. This study, situated in an English academic class for first-year college English majors in Taiwan, aims to explore affordances for students to become more independent and proficient in English writing through translingual awareness development. This article reports on a two-week process by which translingual practice helped foster college students' translingual awareness, which in turn contributed to students' self-directed learning skills. Through the translingual practice with Google Translate (GT), participants performed two writing tasks, reflected on language use in Chinese and English, and leveraged their linguistic repertoires to improve the clarity of their English writing. Data from students' surveys, interviews, and reflection reports were analyzed to show how translingual practice with tools such as GT could help raise students' translingual awareness, which in turn facilitates their self-directed learning to attain proficiency in writing.