Here is a little essay from my training system, The Four Pillars of Singing...
THE SINGING VOICE vs. the speaking voice
At The Vocalist Studio, we don't warm up our voices, more accurately, we warm up to get into our singing voices. If vocalists want to achieve a profound increase in range and enjoy overtones with absolute physical freedom from gripping and inefficient physical ticks, the modern vocalist must learn how to get into his/her "singing voice" and get out of the speaking voice. The speaking voice and all the bodily responses that produce speech is not a platform for producing the singing voice.
When a singer lacks the knowledge and practice of a legitimate voice technique, the brain will send creative commands from the right brain that can not be effectively executed because there simply is no learned behavior or coordinated muscle memory responses developed to drive the singing voice. When this happens, an internal battle between the well intended right brain signals and untrained, physical limitations of the body are out of synch. Yet the show must go one and the body must respond, so it does so by hurling the speaking voice at complex melodic ideas that require the muscles, normally facilitated for speech, to respond in an extraordinary way, it is not designed to do. This is an approach that is inevitably doomed.
Consider this perspective. The Human larynx did evolve to produce speech, but it did not evolve to be able to produce vocal overtones of great volumes, definitive of a singing voice. Unlike animals born to produce vocal overtones, such as whales and birds, the ability to produce powerful vocal overtones and project our communications to great distances, were never critical to the survival of the human race. We don't need to know how to sing to survive, or to feed and breed, like other animals. The point is that students of singing must spend a lot of energy training to facilitate the physics that will transform thier bodies into wind instruments that can produce vocal overtones. To be sure, the process of learning how to sing and the experience of teaching people how to sing, is an abstract endeavor.
However, with practice and physical work outs, the body can be trained to produce the most beautiful and effective overtones of all the animals on Earth and transform a mechanism facilitated for speech, into a system that is the most beautiful instrument of all.
It is widely agreed by musicologists and music lovers of all points of reference that the human singing voice, when properly aligned, is the most beautiful and most versatile instrument of all, capable of producing athletic feats that no other musical instrument can.
The singing voice and the speaking voice are two very different kinds of vocal systems. The speaking voice and all the physical attributes involved in producing speech are not going to drive the singing voice and support modern vocal applications. Getting into your singing voice is an abstract art form and therefore, in order to train a modern vocalist, we must work to develop new muscle memory responses and increase muscular strength in key areas of the larynx to transform a vocal system evolved to facilitate speech, into a system that can sing.