Welsh school bans students from speaking English
Any pupil at Ysgol Morgan Llwyd in Wrexham caught chatting in English faces punishment.
Repeat offenders not talking in their native language face a trip to the deputy head's office, the Mirror reported.
And, in some cases, parents will be asked to re-think their child's place at the school.
Proud staff at the only Welsh-speaking secondary school in the North Wales town have spelt out the strict rules by sending letters to the parents of the 800 pupils.
The new policy - hoped to encourage fluency in Welsh - has not gone down well with everyone.
"It seems so archaic. Kids can even be punished for speaking English on their break - but it's their break so they should be able to do what they want," one parent said.
"The point is to praise them for speaking Welsh, not punish them for using English. It seems extreme," the parent added.
School governor Alun Jenkins said: "The children who come in and don't know Welsh have a crash course.
"If pupils persistently use English despite being prompted to speak Welsh, then actions are needed," he said.
A three strikes system sees students lose their free time if they disobey.
"If they persist, they are then placed on a language card to monitor their Welsh speaking," he said.