4. The apparatus as claimed in claim 2 , wherein the speech recognition failure check unit comprises a loudness level checker unit for examining an energy level of the input speech signal, and determining whether the input speech signal is compatible with the speech recognition by comparing the energy level of the input speech signal with a predetermined level reference value.
2. The apparatus as claimed in claim 1 , further comprising: a speech recognition failure check unit for determining the plurality of speech recognition failures for the speech data and outputting the check results for the plurality of speech recognition failures.