Hi Cheng-Chia Tseng,
welcome! That's great that you want to help with Chinese!
As a first step, could you have a look at the trad. Chinese .po file here:
https://gitlab.com/inkscape/inkscape-web-i18n
I'd love to.
Usually, traditional Chinese is set to zh_TW locale in many free software. However, I found the site set zh to simplified Chinese (usually set to zh_CN in programs), and set zh-Hant to traditional Chinese.
What should I set the "Laungauge:" field of the po file to, zh_Hant or zh_TW?
and (if you haven't done so yet) take a look at the CMS editing
instructions here:
http://wiki.inkscape.org/wiki/index.php/WebSite
and let us know if you have any questions about them?
Access to the website's CMS will be granted after you have made a
contribution (the general rule for Inkscape is 2 contributions).
OK. No problem.
If ever in doubt about something, or if something unexpected happens
(happened to all of us), let us know via mailing list or private email
immediately.
(how would you like to be addressed?)
Kind Regards,
Maren