This study is on the development of English vocabulary skills of selected High School and College students of Bukidnon and Cagayan De Oro City. Specifically, it sought to focus on four areas: when teachers develop vocabulary, the teaching techniques employed to develop vocabulary, students' reaction to the activities presented and the behaviors displayed by students to show understanding of new words introduced. An ethnographic approach to classroom observation was used in this study. The descriptive method served as means to analyze and interpret the gathered data on vocabulary development. The data were gathered through the use of cassette recorder and video tape. Actual observation was also conducted by the researchers to the sample classes. Moskowitz' (2006) behavior categories for language students aided the researchers in describing students' reactions to vocabulary activities presented. A total of four hours was allotted for the gathering of data, equivalent to six lessons. Of the six lessons observed, two were tape recorded and four were video-taped. Findings revealed that the development of vocabulary skills was generally done at the beginning of the lesson. There were only few instances in which it was done at the middle of the discussion. Vocabulary was unlocked through the use of context clues varying from semantic definition, explanation, description and appositive clues. Students enjoyed guessing the words' meaning when used in context that choral responses were prevalent. They manifested that they understood the meaning of the new words developed by using the words in exact context during the lesson activities. [For the complete proceedings, see ED601080.]