Shouting at unruly pupils is taking its toll on Hong Kong teachers, with one in three developing voice problems within four years, a survey has said.
Shouting at students in the class is affecting the voices of teachers in Hong Kong.
A survey said dry throats and husky and harsh voices were among the symptoms reported by teachers, with female sufferers claiming they developed voices like men.
Researchers claim the problem leads to an estimated public loss of almost $1 million a year as a result of 8,380 sick days.
The survey carried out by the University of Hong Kong found the number of teachers with voice problems doubled within the first year of teaching from 15.4 percent during their training year. By the fourth year, this figure had risen to 36.5 percent.
Head of the university's division of speech and hearing services, Edwin Yiu Man-lai, said teachers needed to be taught more non-verbal ways of managing lessons, plus breathing and voice techniques.
Yiu said such problems if left unchecked could develop into voice nodules, which could be permanent and lead to early retirement.