1. A system for checking a spelling of an input English noun word comprising: an input means for inputting an English word; a dictionary memory for storing a plurality of English words which are classified into a first group and a second group, said first group including noun words and said second group including non-noun words, the noun words being stored in a specified memory region storing only noun words in the dictionary memory, said memory region being divided into four blocks including a first block of words whose plural forms can have a common suffix "s"; a second block of words whose plural forms can have a common suffix "es"; a third block of other words of singular form; and a fourth block of words each of which is a plural form of each word in the third group; a search means for searching whether or not an input word exists in the dictionary memory; a suffix judgment means for judging whether or not an input word which does not exist in the dictionary memory has a possessive suffix and, if the input word has a possessive suffix, for searching through the first group in the dictionary memory to find, in cooperation with the search means, word data coincident with the input word without the possessive suffix; and an output means for displaying the input word and indicating whether or not the input word is spelled correctly.