Drawing from health-crisis communication literature and anchoring the study on what we have coined as Dressler-Schmidt's endangered language model, we aim to explore the extent to which COVID-19 pandemic has become a language endangerment window for users of English as a second language (ESL) in Nigeria. To achieve this, data was collected from respondents via online questionnaires and follow-up interviews. The analysis of the data was done using frequency count and percentage while that of the interview responses was done thematically. Overall, the analysis reveals that Nigerian languages are facing a serious linguistic dislocation amid the COVID-19-crisis communication. The paper concludes that the wheel of language endangerment may keep rolling in the multilingual Nigerian society and can get accelerated by any health-crisis communication. We, therefore, propose a COVID-19-crisis communication model to slow down the language endangerment flame in the country.