1. A method for assessing intelligibility of speech represented by a speech signal, the method comprising: providing a speech signal; performing a feature extraction on at least one frame of the speech signal so as to obtain a feature vector for each of the at least one frame of the speech signal; inputting the feature vector to a statistical machine learning model so as to obtain an estimated posterior probability of phonemes in the at least one frame as an output including a vector of phoneme posterior probabilities of different phonemes for each of the at least one frame of the speech signal; performing an entropy estimation on the vector of phoneme posterior probabilities of the at least one frame of the speech signal so as to evaluate intelligibility of the at least one frame of the speech signal; and outputting an intelligibility measure for the at least one frame of the speech signal.