CracklesOther namesCrepitations, ralesCrackles heard in the lungs of a person with pneumonia using a stethoscope.Pronunciation/ˈrɑːlz/(listen)RAHLZ or /ˈrælz/RALZ[1]SpecialtyPulmonologyCrackles are the clicking, rattling, or crackling noises that may be made by one or both lungs of a human with a respiratory disease during inhalation. They are often[citation needed] heard only with a stethoscope..