Within the framework of pragmaticalization, this research, using data from ELC, BNC, and COHA, provides a detailed case study of the English attitudinal marker frankly. By incorporating qualitative and quantitative analyses, the present research portrays the contextualized semantic-pragmatic meanings and syntactic changes of frankly, together with the changes in frequency. As an essentially diachronic study, this paper is a complement to the fields of pragmatics and corpus linguistics that tend to take synchronic data as their sources.