I work in aged care and my employer said they will only allow staff to speak English, even at break times. Is this allowed?

While nurses and care workers are required to speak English in the workplace this rule should not apply to break times, including breaks taken in the staff room, as this could be unlawful. You should seek advice from the NSWNMA if you are being asked to only speak English during your work breaks, even if you do not leave the facility to take those breaks.