yīn
sound
Originally the same as 言 (speech) but with an extra line added in the mouth (口) to distinguish the two characters.
Components
Evolution

Bronze script
Qin dynasty (221-206 BC)
Seal script
Shuowen (~100 AD)
Clerical script
Eastern Han dynasty (25-220 AD)Regular script
ModernDefinitions
yīn
sound, tone, pitch, pronunciation; sound; noise; note (of musical scale); tone; news; syllable; reading (phonetic value of a character)
Component uses
Sources
季旭昇《說文新證》p.164-165