The primary purpose of this research is to determine whether the implementation of Guided Language Acquisition Design (GLAD) teaching strategies increases the English receptive language and expressive vocabulary development of native Korean-speaking students. A secondary focus of the study is to identify specific GLAD strategies that are observed to be effective at supporting the expanding vocabulary of students. Because English language learners need to learn and use vocabulary words for different purposes and in different contexts, this dissertation is focused on vocabulary development for second language acquisition that is not in the context of reading.

Participants included 16 native Korean-speaking students (grade 1, N = 11; grade 2, N = 5) and their teachers ( N = 7). The teachers used seven GLAD strategies to implement their science curriculum over a period of approximately 7 weeks. All of the teacher resources that were necessary to implement the GLAD strategies were provided.

Quantitative data were collected on curriculum dependent as well as curriculum independent measures and were analyzed using paired-samples t tests to determine if growth occurred in the student's English receptive and expressive vocabulary development. Results indicate that curriculum independent measures produced findings that were statistically significant in receptive language only, at least at the small sample size. Curriculum dependent measures, however, did produce findings of learning gains that were statistically significant in both areas. These findings suggest that when vocabulary words are carefully selected from the curriculum, intentionally taught and implemented through a variety of strategies, it is possible that receptive language and expressive vocabulary growth may occur on targeted vocabulary.

Qualitative data were also collected through teacher interviews, observation checklists, and web-based teacher questionnaires. The qualitative data were coded and analyzed for patterns to provide information on the implementation and effectiveness of the GLAD strategies. Three strategies, the cognitive content dictionary, total physical response, and 10/2, were identified as strategies that were (a) used frequently, (b) showing effective use when implemented, and (c) used to teach the target vocabulary words. Qualitative data also revealed that these three strategies were used throughout the day and not exclusively during science.