Study on Dynamic Development of Interlanguage Based on Relationship between Input Hypothesis and Zone of Proximal Development

By comparing the relationship between two kinds of concept such as input hypothesis and proximal development zone, this article is trying to expound the significance making on interlanguage as well as the implications in foreign language learning. The author think Vygosky 's zone of proximal development and Krashen 's i+1 theory has a strong inner relations but differences from angle of consideration and starting point. The former is about goal and result, the latter is way and method, and both of them are advancing and developing constantly in the process of second language acquisition