The purpose of this study was to examine preservice teachers' (PSTs) perceptions regarding their knowledge of the English as a Second Language (ESOL) domains as suggested in the Florida Teacher Standards for English as a Second Language Endorsement (FTSEE), their beliefs regarding the types of assessments and assignments that provided them with the best method of understanding the ESOL domains, and other factors they perceived as influencing their understanding. This mixed methods study collected both quantitative (survey) and qualitative (interview) data. Study participants were elementary education majors enrolled in an ESOL infused program model. Findings from the study indicated that PSTs had an overall understanding of the ESOL domains and were prepared to incorporate a wide variety of instructional strategies and methods into their lesson plans. While culturally competent, they had not yet developed the understanding of how to take an advocacy approach to empower their students in both the school and community. While some PSTs demonstrated a basic understanding of the components of oral language and literacy development in ELLs, many had not yet obtained an in-depth understanding of the specific language thresholds at each language proficiency level nor understanding of the grammatical and linguistic complexities of spoken and written English. These findings imply that further development is needed so that PSTs are better prepared in the following competencies: the ability to write language objectives across the content areas based on the output of oral and written language; the ability to select the appropriate instructional strategies, curriculum, and materials based on language proficiency levels; and the ability to interpret and make informed decisions based on ELLs' assessment results. PSTs valued assignments and activities that allowed them to integrate their own knowledge base into scenarios that might actually occur when they become teachers, or reflected scenarios encountered in teaching situations. They valued opportunities to observe and work with ELLs in the field and desired more opportunities to work with a larger variety of language proficiency levels and ages. Outside influences such as jobs, own school experiences, knowledge of another language, and societal interactions also contributed to their ESOL knowledge. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection