12. An apparatus for machine-translating a first language into a second language, comprising: an example storing unit that stores therein a first-language example in association with a second-language example that is a translation of the first-language example; a rule storing unit that stores therein a rule of a correspondence relation between the first language and the second language; a receiving unit that receives a first-language speech; a first recognizing unit that recognizes the first-language speech as a first-language character string, and outputs a first recognition result; a second recognizing unit that recognizes the first-language speech as a most probable first-language example from among first-language examples stored in the example storing unit, calculates a first likelihood indicating a certainty of the most probable first-language example, and outputs a second recognition result including calculated first, likelihood; a retrieving unit that retrieves, when calculated first likelihood exceeds a first threshold, a second-language example corresponding to the second recognition result from the example storing unit; and a rule-based translating unit that translates, when the calculated first likelihood is below the first threshold, the first recognition result into a second-language speech based on the rule.
12. An apparatus for machine-translating a first language into a second language, comprising: an example storing unit that stores therein a first-language example in association with a second-language example that is a translation of the first-language example; a rule storing unit that stores therein a rule of a correspondence relation between the first language and the second language; a receiving unit that receives a first-language speech; a first recognizing unit that recognizes the first-language speech as a first-language character string, and outputs a first recognition result; a second recognizing unit that recognizes the first-language speech as a most probable first-language example from among first-language examples stored in the example storing unit, calculates a first likelihood indicating a certainty of the most probable first-language example, and outputs a second recognition result including calculated first, likelihood; a retrieving unit that retrieves, when calculated first likelihood exceeds a first threshold, a second-language example corresponding to the second recognition result from the example storing unit; and a rule-based translating unit that translates, when the calculated first likelihood is below the first threshold, the first recognition result into a second-language speech based on the rule. 13. The apparatus according to claim 12 , wherein the first-language example includes a variable portion denoting a replaceable word, and the second recognizing unit calculates the first likelihood for a portion of the first-language example with the variable portion excluded.