This study investigated Reading Recovery teacher understandings about language and early literacy acquisition by applying a constructivist grounded theory design. Participants were Reading Recovery teachers working across three varied districts in Massachusetts (N=33). The purpose of the study was to engage Reading Recovery teachers in surveys, focus groups, interviews, and observations to understand the degree to which Reading Recovery teacher participants value varied student language patterns. Addressing biases faced upon school entry by children who speak differently than their teachers is essential. When students are identified for early literacy intervention, an asset-based frame is critical to ensure accelerated growth. The guiding question was, "What do Reading Recovery teachers understand about using language/linguistic diversity as an asset in early literacy acquisition?" What might be learned, in terms of Culturally and Linguistically Sustaining Practices (CLSP), from Reading Recovery teachers was also discussed. The theory that emerged is that engaging in reflective processes, communicating theoretical understandings regarding reciprocity, working to expand oral language flexibility and a call to continue to grow collective expertise specifically to support linguistic diversity were all necessary. The observation portion of this study found evidence of Reading Recovery teachers working to be culturally and linguistically responsive to all children including multilingual, multidialectal, and monolingual students. Five examples included in the discussion are 1. Daily explicit instruction around literary structures 2. Personalized instruction 3. Positioning the child as a writer: allowing the syntax and meaning of a child to drive conversations and determine the written message 4. Never invalidating a child's syntax or semantics while fostering syntactic flexibility 5. Embedding a Told and then restating that unknown word in a meaningful phrase. Implications for pedagogical practice included working within a CLSP framework to deepen educator understandings of how to honor and teach into linguistic diversity as a strength and develop more robust theoretical and practical collective expertise on the matter. Implications for further research include deepening the connection between Reading Recovery and CLSP. Finally, in the larger field of education the work of culturally sustaining practices and linguistically sustaining practices may need to be discussed as both individual and intertwined issues. [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.]