In today's world where everyone is considered a member of the global village, English has long been regarded as one of the most popular languages for people speaking different mother tongues to communicate with one another. English learning thus appears to be a hot trend in many countries where English is not the official language. Taiwan is a good example to illustrate the current craze of English learning. The authorities concerned and many parents seem to be strong upholders for the popular folk belief that the younger a child starts learning English, the better ultimate proficiency level he or she is likely to achieve, and thus urge young children learn English as early as possible. A number of scholars and parents, however, have raised concerns about whether young children' native language (L1) development would be affected by such overinvestment of time and energy on the second language (L2). Little research has been done to investigate how Chinese young children's L1 development may be affected by their simultaneous learning of an L2. In this paper, the Chinese invented spelling of a 9-year-old bilingual child, who has been attending English-only school since the age of 4, was analyzed from the perspectives of developmental patterns, sociocultural nature, and political and interpretive functions. By examining the child's early written production over a period of two years, the present study aims to discuss how the learning of a second language might affect the literacy development of a bilingual child's L1.