Hi Tsz Yau,
The BrillKids Chinese curriculum can be purchased as a separate add-on package to Little Reader.
We have parents who have started using the Chinese curriculum after they had finished the two English curriculum semesters and we also have parents who are using them in together at the same time.
I think it all depends on how your child reacts and if they are comfortable in learning something extra. I suggest trying out a few lessons in the Chinese curriculum after playing the daily lessons to see how your child reacts.
The Chinese Curriculum Free Trial can be downloaded from your account management page after logging into your BrillKids account:
http://www.brillkids.com/user/#purchases/littlereaderI hope this information helps, let me know if you have any problems