16. The method of claim 14 , further comprising: displaying the first sub key button together with information about the first word on the display unit.
16. The method of claim 14 , further comprising: displaying the first sub key button together with information about the first word on the display unit. 20. The method of claim 16 , further comprising: displaying the first and second alphabet characters in the text window as a first style; and displaying the rest of the alphabet characters in the text window as a second style different from the first style.