Singapore Expats

I am a parent who came from Europe last year and decided to join CNIS because of the high immersion of Chinese.
I must say I am very happy with the Chinese teachers and Chinese curriculum. From our previous school, it is quite obvious that whilst CNIS is on an old school site, and has not had a great reputation from what I understand in the past, I found that the level of teaching was more advanced comparend to what my son had been taught in Europe.
I also love the mix of nationalities and diverse set of parents which is something I like.

I would receommend CNIS to anyone looking for something out of the ordinary.

My children go to a Mandarin Immersion school in the US and I would like to keep them in Mandarin Immersion if we move to Singapore so they can return to the program when we return to the States.

What is the difficulty of the Chinese in primary school? My older son is in 2nd grade, is studying simplified Chinese and pinyin and can ready simple books especially if there is pinyin. My younger will be entering kinder. Is there differentiated learning for those that speak mostly English at home and those that speak Chinese at home.

What is the source of it's previous reputation? Is it strict? Are there mostly Chinese expats or is it more international?