As a researcher, I am continuing my research to apply the common language standards studied in graduate school to elementary school, with the phrase ‘theory into practice' as my goal. Through a graduate school master's course study, the language awareness of elementary school learners in Korea was investigated at the CEFR Basic User level through self-evaluation, and their performance was created and evaluated according to the CEFR scale. Through this research, the graduate school's doctoral program conducted primary research to compare and analyze Korea's English department curriculum by CEFR stage and researched utilizing CEFR in school settings. Among the communicative language activities and strategy elements of CEFR, mediation is a communication function required to convey and clarify one's thoughts in another country's language. It is one of the competencies that future learners in the 21st century must have, and it is included in our country's curriculum. I conducted field research with the idea that it must be actively reflected in teaching, learning, and evaluation. For CEFR to be applied to the domestic curriculum, a practical survey must be conducted on the English level of Korean learners. The researcher investigated the vocabulary level of elementary school learners using CEFR EVP through a study on meaning and usage at each level and analyzed it at the Basic user level and textbook usage. When presenting vocabulary, our country's curriculum and textbooks give one Korean meaning for each vocabulary. As a teacher, I continue conducting research using CEFR to design and evaluate teaching and learning appropriate to the actual level of learners. Additionally, I am working with pre-service teachers at a university to explore teaching and education relevant to the developmental stage of elementary English learners. Future teachers are the ones who directly apply and lead the 2022 revised English Department curriculum in the field, and I believe that a proper understanding of the curriculum and learners is a critical element of English education in our country.