The purpose of this study is to examine the roles which English dictionaries play in learners" production activity and to raise awareness about the necessity for more explicit guidance for English learners who wish to use English dictionaries to enhance their accuracy in production and vocabulary knowledge. For this purpose, first of all, the notion of knowing a word or a set of lexical items, along with the problems that learners possibly encounter when they attempt to encode their messages are reviewed with previous studies. Second, it illustrates the elements and characteristics of information which typical English learners" dictionaries provide for users in the light of difficulties involved in production activity. Third, this study analyzes the content and structure of current major encoding dictionaries of different types and purposes, assessing their distinguishing features and complementary advantages. It is hoped that the findings of this study develop the dictionary awareness among English learners and educators in Korea.