4. The apparatus of claim 1 , wherein the first error detector comprises: a part-of-speech sequence generation unit configured to generate the part-of-speech sequences in units of predetermined windows using the n-grams of the parts of speech tagged to the sentence; a shallow parser configured to calculate degrees of closeness of the part-of-speech sequence by parsing the part-of-speech sequences based on context free grammar (CFG) rules and regular grammar rules; and a first error detection unit configured to detect the first grammatical errors in the sentence according to the degrees of closeness calculated by the shallow parser.
4. The apparatus of claim 1 , wherein the first error detector comprises: a part-of-speech sequence generation unit configured to generate the part-of-speech sequences in units of predetermined windows using the n-grams of the parts of speech tagged to the sentence; a shallow parser configured to calculate degrees of closeness of the part-of-speech sequence by parsing the part-of-speech sequences based on context free grammar (CFG) rules and regular grammar rules; and a first error detection unit configured to detect the first grammatical errors in the sentence according to the degrees of closeness calculated by the shallow parser. 5. The apparatus of claim 4 , wherein the CFG rules are obtained by standardizing general grammar including a spelling system, articles, and tenses.