A free program for Android, by Kumao.Works.

It allows you to record videos with any voice you want and then change the pitch and the formants at the same time.

Because this app changes the pitch and the formants at the same time, it can be used to change the sound of the entire video from male to female, from child to adult, from one language to another, and even from one country to another. It can also be used to change the sound of the background of the video.

The voice will be converted into a natural sound, so you can feel that you are in the real world and not in a recording studio.