The answer to this is letterTone Color. Some people are more familiar with this as timbre. There are different types of sounds that you can hear in this world. You can expect that the pitch will always be different. The tone in sounds can be a bit confusing for some people. They do not understand that there are differences that should be noted depending on the sounds that they hear.
The different types of sound productions can be used not only for the voices of people but also for the sounds that are made by the different instruments that are available. Remember that timbre is not characterized by how loud or how soft the sound is.