A system of implementing flexible keyboard layout for inputting text into an electronic device, where a user's input is mapped to a character set based on a keyboard layout, and an input sequence is formed. The user may customize different keyboard layouts and switch among these different layouts arbitrarily. Also, an auto error-correction may be achieved, and smart words selection may be achieved based on context. With the system of the invention, the design cost of the portable device manufactures may be reduced significantly.