A voiceless sound is a type of speech sound that is produced when the vocal cords do not vibrate. It is usually associated with consonants such as "p", "t", and "k". There are several synonyms for voiceless sound including unvoiced sound, surd, or non-phonemic consonant. These terms are often used interchangeably in linguistics to refer to sounds that are not produced with the vocal cords. In phonetics, voiceless sounds are contrasted with voiced sounds, which are produced when the vocal cords vibrate. Mastering the use of voiceless sounds is important in language learning and communication, as it affects the clarity and comprehensibility of the spoken message.