8. A correction method of a word or a character substring, the method comprising: displaying, on a screen of a device, one or more words in response to input from a user; moving a cursor to a correction candidate word of the one or more words displayed on the screen according to a cursor movement command from the user, the cursor being located between a position immediately before a first character constituting the correction candidate word and a position immediately after a last character constituting the correction candidate word; displaying, on the screen of the device, a new character substring at a location of the cursor on the screen in response to input from the user after displaying the one or more words on the screen; calculating a correlation between character substrings constituting the correction candidate word and the new character substring based on a proximity of keys for the character substrings and keys for the new character substring on a keyboard; determining whether or not to register the at least one of the character substrings constituting the correction candidate word in a correction candidate list based on the calculated correlation; receiving a correction command input from the user; if only one of the character substrings registered in the correction candidate list, replacing the character substring registered in the correction candidate list with the new character substring, in response to the correction command, such that the new character substring is displayed at a location where the character substring registered in the correction candidate list was displayed; and if two or more of the character substrings are registered in the correction candidate list: replacing a first character sub string of the two or more of the character substrings displayed on the screen with the new character substring, such that the new character substring is displayed at a location where the first character substring was displayed; and replacing a second character substring of the two or more of the character substrings displayed on the screen with the new character substring, in response to a move command, such that the new character substring is displayed at a location where the second character substring was displayed.
8. A correction method of a word or a character substring, the method comprising: displaying, on a screen of a device, one or more words in response to input from a user; moving a cursor to a correction candidate word of the one or more words displayed on the screen according to a cursor movement command from the user, the cursor being located between a position immediately before a first character constituting the correction candidate word and a position immediately after a last character constituting the correction candidate word; displaying, on the screen of the device, a new character substring at a location of the cursor on the screen in response to input from the user after displaying the one or more words on the screen; calculating a correlation between character substrings constituting the correction candidate word and the new character substring based on a proximity of keys for the character substrings and keys for the new character substring on a keyboard; determining whether or not to register the at least one of the character substrings constituting the correction candidate word in a correction candidate list based on the calculated correlation; receiving a correction command input from the user; if only one of the character substrings registered in the correction candidate list, replacing the character substring registered in the correction candidate list with the new character substring, in response to the correction command, such that the new character substring is displayed at a location where the character substring registered in the correction candidate list was displayed; and if two or more of the character substrings are registered in the correction candidate list: replacing a first character sub string of the two or more of the character substrings displayed on the screen with the new character substring, such that the new character substring is displayed at a location where the first character substring was displayed; and replacing a second character substring of the two or more of the character substrings displayed on the screen with the new character substring, in response to a move command, such that the new character substring is displayed at a location where the second character substring was displayed. 9. An input device for correcting a word or a character substring according to the method of claim 8 .