A free program for Android, by Complete Vocal Institute.
The aim is to teach and improve your voice by discovering how to use your muscles, bones, and airways to produce different sounds. The tools and techniques are easy to understand, practical, and scientifically proven to work. There is a vast library of images, sounds, and exercises to help you improve your voice.
How do I get started?
Download the Complete Vocal Technique app and choose your first lesson. You can start with the first lesson and work your way through the lessons. You can practice the lessons at home, and they are also useful for recording and singing.