Hi babymum,
Can you tell us which specific font you have set for the Chinese category that you're working on?
> In Little Reader's Advanced Play/Edit screen, select the category you have this problem in
> Toggle the "Playback Settings" tab for this category and check which font option is selected under "Words > Font type"
In the meantime, you may try changing the font and see if it helps (if you have the Chinese curriculum, you should see 4 Chinese font options). Alternatively, you can also use your own Chinese font for your lesson by selecting "Custom..."
Please see this article for details on customizing your playback settings:
http://support.brillkids.com/entries/20384553-how-to-customize-your-playback