14. The apparatus of claim 12 , wherein the controller is configured to present the candidate words in order of high similarity by presenting corresponding candidate words in ascending order of calculated edit distance.
12. An apparatus configured to assist in avoiding incorrect input in a portable terminal, the apparatus comprising: an input unit configured to receive a user input; a storage unit configured to store data; and a controller configured to, after identifying an input character string from the user input, search a plurality of candidate words recommended for the input character string from among one or more previously registered candidate words, calculate a similarity between the input character string and each of the searched candidate words based at least partially upon a type of keypad used to input the input character string, and display, via a display, one or more of the searched candidate words according to the calculated similarity, wherein the controller is configured to calculate the similarity between the input character string and each of the searched candidate words by identifying the keypad type; determining each cost of an insert operation, a delete operation, and a replace operation correspondingly to the identified keypad type; and calculating an edit distance using the operations according to the respective cost associated with each operation.