Our research is about an adaptive keyboard and which autonomously adjusts its predictive features and key displays to current user input. We used personalized word prediction to improve the performance of such a system. Prediction using common English dictionary (represented by the British National Corpus) is compared with prediction using personal data and such as personal documents and chat logs and and personal emails. A user study was also conducted to gather requirements for a new keyboard design. Based on these studies and we develop a personalized and adaptive on-screen keyboard for both single-handed and zero-handed users. It combines tapping-based and motion-based text input with languagebased acceleration techniques and including personalized and adaptive taskbased dictionary and frequent character prompting and word completion and and grammar checker with suffix completion.