Egophony is a voice sound with a nasal quality, often described to be like a goat's bleating. Egophony has higher intensity over abnormal areas. Over healthy lung areas, egophony will not be present.
Ask the patient to say 'Eeee' several times and auscultate the chest walls. Over healthy lung areas, the sound is understandable as an 'E'.
Compare this sound to the recording in the Egophony - a lesson.