Voiced and Unvoiced sounds

 Voiced Sounds: These sounds are produced when your vocal cords vibrate. Think of most vowels (a, e, i, o, u) and many consonants like 'b', 'd', 'g', 'v', 'z', 'm', 'n', 'l', 'r'. The vibration of your vocal cords creates the "voiced" sound.

Unvoiced Sounds: These sounds are produced when your vocal cords do not vibrate. The sound is created by the obstruction or friction of air in your vocal tract. Examples include consonants like 'p', 't', 'k', 'f', 's', 'sh', 'ch', 'th' (as in "thin"). These sounds are "voiceless" or "unvoiced".

Exersice:  try pronouncing a 'b' and then a 'p'. Feel the vibration in your throat for the 'b' (voiced sound) and the lack of vibration for the 'p' (unvoiced sound).