The article investigates how formal classroom instruction and informal natural exposure operate in the context of second language development, especially with reference to the development of oral proficiency in English as a second language. The author argues that the significance of the study lies in the fact that the field study was conducted in Nepal which provides a unique opportunity for this kind of study. It is one of the few countries in the world where there exist possibilities for people to learn English through their exposure to mutually exclusive formal and informal language learning environments. The study suggests that formal and informal language learning environments contribute to second language development in different ways. The former seems to promote accuracy and the later seems to promote fluency. (Rajeev Ranjan Singh 2007-02-21)