Appraisal analysis of the vague expressions in academic lectures using English as an academic lingua franca in an EMI university

This study aims to compare how lecturers, also being different English as a lingua franca (ELF) users use various vague expressions in academic lectures in a Chinese English-medium instruction (EMI) university. The study adopts the framework of appraisal grounded in systemic functional linguistic theory to classify all vague expressions according to intensity, amount, and categorisation. It is found that vagueness in relation to amount with no gradable features was used most frequently in the 12 academic lectures of the study, followed by those related to no-scaled categorisation and upscaled intensity. The use of vague expressions is further examined from an academic ELF perspective. We discover that native-speaker lecturers may use more vague expressions concerning amount whereas ELF lecturers may prefer those concerning intensity. Finally, we suggest some pedagogical implications of using vagueness in ELF communication for delivering academic lectures in the EMI university context.