My case is bit changeling...at least for me…

I have a bilingual bookstore website (www.best4future.com). Right now I am selling Chinese books. So you can see(The category is on the right side of the website.
), the pointer image is a Chinese flag before each category (e.g. learn Chinese, Chinese story books, Chinese multimedia). But I want to expand the bookstore to French, German, Spanish and Japanese.

And I want to use a French flag for all the categories relating to French language (e.g. learn French, French story books, French multimedia). The same, a German flag for all the categories relating to French language (e.g. learn Germany, Germany story books, Germany multimedia).

Is there any way to achieve that? Thank you so so much!!