Patent US 5,148,367

A word processor with a spelling correction function. A spelling error can result from for example, improperly inputted characters or misread characters. When the improperly input or misread characters are not found, for example in a main dictionary or a user's dictionary of the word processor, characters from a probability table are selected to replace the improper characters which have been caused by the spelling errors. The probability tables can be formed by determining from proper inputting into the word processor the highest frequency of appearance order of two characters. In addition, the probability table can be made by determining the frequency of corrections of an improperly inputted character. When the proper character is added to the improper character which caused the spelling error, the proper character is compared with the main or user dictionary and when it is determined that the character is in the main or user dictionary the character sting is outputted as the correct word from an output portion of the word processor.