Ecological linguistics is a new subfield increasingly gaining popularity by reason of the growing awareness of the need for sustainable development. Assessing education for environmental sustainability development is fundamental in ensuring learners acquire the necessary knowledge, skills, and attitudes to participate in sustainable development practices. Ecological linguistics supports a framework for examining how language is used to structure learning and understand the natural environment. Additionally, it examines how language can advance or hinder sustainable development practices. The article presents a case study at RUDN University, where ecological linguistics assessed ecological knowledge and awareness literacy levels. The study found that language extensively shapes learners' understanding and attitudes towards the natural environment. The article concludes by emphasizing the perspective of assessing education for environmental sustainability development.