Final answer:
The organ used for phonation is known as the larynx or voice box, located in the respiratory system and houses the vocal cords necessary for producing vocal sounds.
Step-by-step explanation:
The anatomic organ used for phonation is called the larynx, which is often referred to as the voice box. It is a critical component of the respiratory system located between the pharynx (a tubular organ that connects the mouth and nasal cavity with the larynx and through which air and food pass) and the trachea. The larynx contains the vocal cords, which are essential for the production of vocal sounds. When air passes through the vocal cords, they vibrate, creating sound. This sound can be modulated by the tongue, mouth shape, and other parts of the vocal tract to produce the wide variety of sounds necessary for human speech.
Human speech is generated by shaping the cavity formed by the throat and mouth and adjusting the vibrations of the vocal cords along with using the tongue. This intricate process allows us to create a spectrum of overtones and varying intensities of sound, which contribute to the uniqueness of each individual's voice.
The larynx plays a vital role in both speaking and breathing and is protected by a cartilage structure. The evolution of the larynx and the vocal tract is thought to have played an important role in human evolution, giving rise to complex language and communication.