11. A method comprising: when a word is selected and then a change key is entered, and a first character of the word is a capital letter, changing the first character to a small letter; when the change key is entered during a display of the first character of the word with the small letter, comparing a number of capital letters of the word and a number of small letters; when the number of capital letters of the word is greater than the number of small letters, changing all characters of the word to capital letters; and when the number of capital letters of the word is less than the number of small letters, changing all characters of the word to small letters.
11. A method comprising: when a word is selected and then a change key is entered, and a first character of the word is a capital letter, changing the first character to a small letter; when the change key is entered during a display of the first character of the word with the small letter, comparing a number of capital letters of the word and a number of small letters; when the number of capital letters of the word is greater than the number of small letters, changing all characters of the word to capital letters; and when the number of capital letters of the word is less than the number of small letters, changing all characters of the word to small letters. 15. The method of claim 11 , further comprising: when partial characters including the first character of the word are selected and then the change key is entered, and the first character of the word is the capital letter, changing remaining characters, except for the first character, among the partial characters to small letters; and when the change key is entered during a display of the word of which only the first character among the partial characters is a capital letter, changing all characters of the word to small letters.