1. A speech processing apparatus, comprising: an entity extracting unit to extract entity information by extracting input speech entity information from input speech and extracting a respective upper entity from a respective same domain as the input speech entity information; a focus determination unit to determine a focus of the input speech using extracted input speech entity information requiring a response from among a plurality of the extracted input speech entity information and preset entity information requiring a response, wherein the preset entity information requiring a response is pre-stored separately from other entity information; a mapping unit to map lower domain entities, of the domain, corresponding to the focus with the extracted input speech entity information; and a recognition unit to recognize a result of arranging the extracted input speech entity information according to semantic association among the mapped lower domain entities, of the domain, as the input speech, wherein the upper entity is a hierarchically higher entity, within the domain, than the lower domain entities, the semantic association among the domain entities is preset, and entity portions within the extracted input speech entity information are determined to be semantically associated with one another according to the preset semantic association, and wherein the recognition unit performs recognition of the input speech within pre-defined categories, respectively as the lower domain entities, with the lower domain entities being distinguished from the entity portions within the extracted input speech entity information and the recognized input speech.