Dear red.merc49,

My personal view is that before u ask people to change, why not u try to adapt and learn Mandarin/Chinese bit by bit. Working in a team is about team work and trust. U should start by gaining their trust, blend in and then discuss that with them. I am sure Malaysian Chinese is not that bad, u have not seen worse. While u can escalate to management but u will never be in their group and working there become more stressful.
tl;dr, before ask people to change, maybe u can try to adapt and move on. If u find it easy to ask people to change, then it is the same to u, why not.
Ideally, your colleagues should not behave like that, but unfortunately we don't live in ideal world but a realistic world.

I am Chinese but I studied in Catholic school last time, hence my Mandarin is just pasar malam rojak level. I do agree that Chinese came out to defend themselves, because there is no one else will defend them all these years if not they themselves. Back to the context, that is the reason why majority of Malaysian grads are not competitive compared to other countries. Number of grads vs. quality over Asia (Not even across the globe) is low, not saying all but many of them.

I like this part Unfortunately, it was never a fair competition at the first place. Cheers.