This invention discloses a sequential two-key system to input letters of the English alphabet and of many world languages, numbers, punctuation marks, page-control characters, line-control characters, cursor-control characters and many other symbols on keypads with few buttons. Character repeating, shifting and control access are feasible. Brief and easy to understand notations are displayed on the keypads. The system is easy to learn and the keypads may be used on portable devices such as PDA, hand-held computers, hand-held text-messaging devices and telephones.