Here is an account that gave me pause:
An author for READERS DIGEST writes how he studied the Amish people in preparation for an article on them. In his observation at the school yard, he noted that the children never screamed or yelled. This amazed him. He spoke to the schoolmaster. He remarked how he had not once heard an Amish child yell, and asked why the schoolmaster thought that was so. The schoolmaster replied, Well, have you ever heard an Amish adult yell?
Counter Attack, Jay Carty, Multnomah Press, 1988, p. 41ff