yīn
sound
Originally the same as 言 (speech) but with an extra line added in the mouth (口) to distinguish the two characters.
Bronze script
Seal script
Clerical script
Regular script
yīn
sound, tone, pitch, pronunciation; sound; noise; note (of musical scale); tone; news; syllable; reading (phonetic value of a character)
季旭昇《說文新證》p.164-165