The following is a collection of machine learning and speech processing software packages written by others that I have used (extensively – the criteria to make this page!).
Voicebox: A large Matlab collection for speech processing.
LibSVM: C++ and Java package for SVM.
Praat: A GUI for speech processing.
EM4GMM: C code for fast GMM estimation.
TKK Aparat: A Matlab glottal waveform estimation package via inverse filtering.