1. A speech recognition method, comprising: detecting, using at least one processing device, energy changes between a plurality of frames distinguishing portions of a signal, each of the plurality of frames having time lengths less than a whole time length of the signal; and identifying speech segments and/or non-speech segments from the plurality of frames based on the detected energy changes between the plurality of frames by assigning a predetermined weight to a segment in which an energy level of a respective frame is changed and when an energy difference exists between two neighboring frames.