Just as you varied the tension on the rubber to change the sound, you vary the tension on your vocal cords to change your voice. Of course, there is a lot more to speaking than that. Your voice also depends on things such as the force of air from your lungs and the shape of your mouth, tongue and lips. With more practice, you can almost imitate speech with your balloon. Several famous clowns have used this very effectively.
Most musical terms are Italian.
Some are French or German. None are English. This will get you started. Listen to an opera sung in its original language. Look up the different instruments used in the Bible.