Abstract: The technology described herein can improve the operation of a computerized text entry system (e.g., keyboard, speech to text) by making grammatically correct auto-complete suggestions as a user enters text. The technology described herein builds and uses a set of generalized rules that make the auto-complete feature sensitive to the context of what has already been typed, particularly at the level of a sentence or phrase. The technology described herein receives one or more words within a partially completed sentence and outputs one or more contrastive grammatical categories that the next word may be if the final sentence is to be grammatical.