MorphVOX Junior is an excellent free licence programme with which you will be able to run morphing effects on voice sounds and other audio files, in a simple and entertaining manner.
This wonderful and innovative application will allow us to add different modifications to our voice files, creating a new and completely different sound from the original with results that vary from the voice of a man or woman, to the voice of an elf or goblin.
MorphVOX has a simple graphical interface and intuitive options, being an easy to use programme for amateurs as well as computer experts, it is worth mentioning that it has a module called Voice Doctor, that is capable of transforming the sounds made by your vocal cords in real time while you keep up an audio conversation using instant messaging systems or even the worldwide renowned application Skype.