This chapter describes the more regular grammatical features of English as a lingua franca (ELF), and their probable causes, of which three seem to be important. Some regularities involve the simplification of inherently 'difficult' elements of English grammar, those which appear odd or afunctional or idiosyncratic from the perspective of speakers of most other languages. Hunston and Francis, who use the term 'International English' rather than ELF, concede that an International English corpus might show different regularities in patterning than a native speaker corpus, but state that they would be 'very surprised' if overall, no regularities in patterning were shown, as they insist that 'patterning is a necessary feature of language'. Accommodation theory stresses that when people interact, they frequently adjust their speech, so as to approximate the patterns of other participants. At the grammatical level, this 'furniture' might well involve such things as the categories of mass and count nouns, and event conceptualization patterns.