1. A processor implemented speech recognition method, comprising: receiving a recognized sentence generated through speech recognition; evaluating the sentence by calculating a degree of suitability for each word in the sentence that takes into consideration a relationship of each word with other words in the sentence; selecting, by the processor and based on the calculated degrees of suitability, a target word to be corrected among words in the sentence; sampling candidate words, dependent on the selecting of the target word, considering relationships between the words of the sentence and a position of the target word; selecting, by the processor and dependent on the sampling of the candidate words, at least one of the sampled candidate words based on processor evaluated suitabilities of the sampled candidate words; and respectively revising the sentence by replacing the target word with the selected at least one sampled candidate word, wherein the respective revising of the sentence further includes evaluating the respectively revised sentence to determine whether to select another target word of the respectively revised sentence to be corrected before generating a final recognition sentence.