In accordance with an aspect of the present disclosure, there is provided a method for identifying a type of a vocoder. The method comprises acquiring identification target bitstreams encoded with a voice signal, acquiring, for each of a plurality of vocoders, a probability that each of the plurality of vocoders is related to the identification target bitstreams from the identification target bitstreams, acquiring waveforms for each decoder of each of the plurality of vocoders by inputting the identification target bitstreams to the each decoder of each of the plurality of vocoders, acquiring intelligibility values for each of the waveforms obtained for the each decoder of each of the plurality of vocoders from the waveforms, and determining the type of the vocoder related to the voice signal from the probability and the intelligibility values for each waveform.