This room is covered with soundproofing material, so the sound doesn't leak outside.

He honked the car horn to get my attention.

His words are always sweet on the surface but venomous underneath.

Infrasound is a type of sound that is inaudible to the human ear.

Debuccalization refers to the phenomenon in phonetics where a specific sound is pronounced outside the oral cavity.

Kunminjōon is a book for teaching the correct pronunciation of Hangul.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

Understanding the concept of 'Ha-line conversion sounds' is important in learning Japanese.