Can human generate voice frequency more than 20khz by mouth

 

No, humans cannot generate voice frequencies more than 20 kHz by mouth. The vocal cords, which are the primary source of sound production in the human voice, are only capable of vibrating at frequencies up to about 20 kHz. This is the upper limit of human hearing as well, so there is no need for the vocal cords to be able to vibrate at higher frequencies.

However, there are some people who can produce ultrasonic vocalizations, which are frequencies above 20 kHz. These vocalizations are often produced by animals, such as bats and dolphins, but they can also be produced by humans. Ultrasonic vocalizations are typically used for communication over long distances or for echolocation.

In humans, ultrasonic vocalizations are typically produced by the vocal cords vibrating at a very high frequency. This can be done by intentionally tensing the vocal cords or by using a technique called "strobing," which involves rapidly contracting and relaxing the vocal cords. Ultrasonic vocalizations can also be produced by the tongue or lips vibrating at a high frequency.

While ultrasonic vocalizations are possible for humans, they are not very common. Most people cannot produce them without special training or equipment. Additionally, ultrasonic vocalizations are not usually used for communication in humans. They are more likely to be used for medical or research purposes.