aged-care nurses with a lower grasp of English

Seriously, how much lower can this grasp of english get?

I have quite a bit to do with nursing homes and yes, they are very understaffed. But the care staff they do have are seriously struggling with language issues as it is. This means they have trouble understanding what duties are required of them, and often cannot/do not read instructions/labels/signage.

Plus, because we are a multicultural nation, there is often a total - not just partial - language gap between carers and residents, which means that the care quality drops considerably, and confused residents become even more confused.

I don't care what the common language is, but there needs to be a way for carers and residents to communicate.