The COVID-19 pandemic altered human activities in several ways. It affected how people communicate and use language. Nigeria, with over 500 languages and just one official language, exploited multilingual resources to fight the COVID-19 pandemic. This chapter examines multilingualism and linguistic diversity in the discourse of COVID-19 public health awareness campaign messages in Nigeria. Thirty COVID-19 campaign messages in form of posters, audio jingles, videos, brochures, and sociolinguistic field interviews (30 unstructured one-on-one interviews) with some selected members of rural communities were analyzed. The study found that indigenous languages, multimodality, and translations were utilized as mass mobilization tools to promote inclusion. The study concludes that multilingualism and multimodality deliver COVID-19 sensitization messages effectively, increase access, and promote inclusiveness. It further suggests the localization of public health crisis in line with the sociolinguistic dynamics in multilingual settings.