A corpus-based study of explicit objective modal expressions in English

The grammatical pattern of explicit objective modal expressions and its three subtypes (i.e., explicit objective expressions of probability, usuality and obligation) are investigated in this paper. By implementing a collostructional analysis, specifically collexeme analysis and multiple distinctive collexeme analysis, we aim at uncovering how, with respect to different genres in COCA (Corpus of Contemporary American English), modal expressions are significantly attracted or repelled by the grammatical pattern, and how these expressions are diachronically associated with the grammatical pattern in different time periods of COCA and COHA (Corpus of Historical American English). The genre-related findings demonstrate that explicit objective modal expressions of probability and obligation are attracted by formal genres while repelled by informal ones, whereas those of usuality are repelled by both formal academic and informal spoken genres. The diachronic findings demonstrate that modal expressions that denote low values of probability and obligation have undergone a path of gradual change from repulsion to attraction because of an accumulation of negotiability and politeness by language users.