The emoji shows silhouette of speaking person. Lines demonstrating that he is speaking loud. Sometimes contex represents shouting.
Note: Under the name “Speaking Head in Silhoutte” speaking head emoji was accepted as part to Unicode 7.0 and in 2015 added to Emoji
🗣️ Speaking Silhoutte Head
🗣️ Speaking Head in Silhoutte
:speaking_head_in_silhoutte: (Slack)copy & paste emojiemojiemoji meaningspeaking head