Students bring cultural and linguistic richness to the English Language Arts classroom in the form of English language diversity; that being said, English Language Arts (ELA) education has traditionally privileged Standard American English (*SAE) and its related white culture rather than embrace the aforementioned diversity. With calls for more inclusive ELA curriculum and pedagogy that acknowledges and welcomes English varieties to include Black Language (BL), I designed this qualitative case study in order to explore how teachers generate, negotiate, and apply learning around BL. Through this case study -- specifically a collaborative inquiry -- involving survey, interview, and ethnographic data, I investigated ways in which six secondary English Language Arts teachers learned and taught about language diversity, particularly BL. Through Reflexive Thematic Analysis (RTA), I analyzed data and extrapolated four major themes: "Teacher Positionalities and Their Shaping"; "Instruction Around Language Diversity"; "Teacher Concerns and Aspirations"; and "Teacher Reflexivity." These four themes precipitated three critical findings: Teacher inquiry groups are important as safe and critical spaces; more resources and support are needed for teachers engaging in challenging societal issues like language diversity; and ELA teachers are willing and eager to incorporate Critical Language Pedagogy into their practice. These findings extend our understanding of existing practices of continuing teacher education and professional development, offering some specific and concrete suggestions for enhancing English Language Arts pedagogy and curriculum. In particular, because collaborative inquiry groups provide a safe and productive space for teachers to engage with challenging societal issues like language diversity, they should be encouraged and implemented in more educational settings. Furthermore, as highlighted by this study, educators are seeking to incorporate Critical Language Pedagogy into their teaching, and thus require related resources and support to do so effectively. [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.]