VietTESOL International Convention 2026

The 17 Sustainable Development Goals (SDGs) have increasingly informed the development of General English textbooks, including Voices by National Geographic Learning, where themes such as environmental protection, gender equality, health and well-being, decent work, and responsible consumption are used as contexts for language learning. In Vietnamese higher education, such materials are often adopted within wider efforts to internationalize curricula, improve English proficiency, and expose students to global issues. However, the inclusion of SDG-related themes in a textbook does not necessarily mean that such learning is clearly connected to classroom assessment or institutionally valued as assessable evidence. Using constructive alignment as the main theoretical framework and assessment washback as a supporting lens, this case study first examines how Voices by National Geographic Learning represents SDG-related themes and connects them to language-learning tasks in Vietnamese tertiary General English courses. It then investigates how seven Vietnamese tertiary EFL teachers using this textbook enact, assess, or leave unassessed SDG-related learning, and what forms of alignment or misalignment emerge across textbook content, classroom practice, and assessment artefacts. The findings suggest that sustainability is pedagogically visible but assessmentally weak. Teachers recognized SDG-related themes in Voices and sometimes extended them through examples, discussion, or group work, but they reported limited clarity about learning outcomes, assessment criteria, or links to formal testing. In classroom practice, assessment often recentered language accuracy, correct answers, participation, and task completion, reducing sustainability to a context for language practice. The study argues that sustainability-oriented ELT in Vietnamese higher education requires more than textbook-based topic inclusion; it requires assessment designs that make SDG-related learning visible, interpretable, and pedagogically useful within existing General English program requirements.