This qualitative descriptive study aimed to explore how English as a Second Language (ESL) and Language Arts teachers describe how they use morphology structure instructional strategies to support ESL students' vocabulary development in the United States. This research study's theoretical foundation focused on the seven-step process pre-teaching vocabulary strategy created by Dr. Margarita Calderon. The research study consisted of one overarching research question with three subsequent questions. This study used a qualifying questionnaire, interviews, and focus groups where all participants signed the informed consent before participating in the qualifying process. The researcher selected 10 participants based on their responses to the qualifying questionnaire that meet the minimal requirements to participate in the study. Thematic analysis was conducted after the data collection from the interview and focus group to develop codes and identify themes. As a result, the following themes were developed in response to the research question and research sub questions: (1) vocabulary development strategies and morphology awareness/word comprehension; (2) vocabulary development strategies and teacher resources; (3) assessment tools and strategies that lead to morphology awareness and comprehension; and (4) vocabulary development strategies and phonemic awareness settings. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]