It's rude to yell.
Four year old Brian has just returned from his first day of school with lots to tell; his mother unfortunately has a headache.
Brian wants to share his day with his mother.
Brian starts talking rapidly, but keeps his voice at an appropriate level for indoor conversation, telling his mother everything about his day.
Brian starts talking very loudly and rapidly, trying to tell his mother everything at once.
Brian's mother listens, smiling and nodding at Brian's enthusiasm.
"Brian's mother puts her hands over her ears because the yelling is hurting her headache, ""Please use your indoor voice"" she pleads."