Ingressive sound
When we talk or make sounds, air comes out of our mouth or nose. That is called egressive sound. But sometimes, when we make sounds or talk, air is sucked into our mouth or nose instead of going out. That is called ingressive sound.
For example, try humming while breathing in instead of breathing out. You will notice that you are making a different sound and air is going into your nose. That is an example of ingressive sound.
Some languages have sounds that are made through ingressive airflow, such as the "click" sounds in some African languages. Overall, ingressive sound is just a different way of making noise by sucking air in instead of blowing it out.
For example, try humming while breathing in instead of breathing out. You will notice that you are making a different sound and air is going into your nose. That is an example of ingressive sound.
Some languages have sounds that are made through ingressive airflow, such as the "click" sounds in some African languages. Overall, ingressive sound is just a different way of making noise by sucking air in instead of blowing it out.