The loud volume of voice that teachers use. It's not really a yell since that indicates fear or anger--just the loud, obnoxious voice of someone accustomed to endeavouring to speak over the crowd without sounding angry. Off-duty teachers often don't know they are being too loud and coming off as bossy.
"If you're getting up, would you bring me a glass of water?"

"Stop shouting, I'm right next to you. You've been shouting since you got here."

"Sorry, it's my teacher voice."
by The Ripper November 23, 2006
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