General settings in the Customer Portal is not translated to Chinese

Problem definition

The multilingual service desk is not implemented in Server, thus it's expected to see fields and some settings in English regardless of the customer's profile language. Nevertheless, for some languages like Japanese and German, all general settings are correctly translated. However, if a user uses Chinese as the profile language, everything remains in English.

This also affects Service Desk Screens in JIRA Administration, such as the "JIRA Service Desk Configuration" screen

Steps to reproduce the problem

1. Change the JIRA default language to Chinese.
2. Log in to the portal and verify the profile language as Chinese.
3. Go to the main portal page and observe the display language.
4. Change the language to Japanese.
5. Go to the main portal page and observe the display language.

Expected result

Many settings/buttons/links are displayed in the language same as the profile language, for example, the page below shows some options in Japanese when using Japanese.

Actual result

The profile page is displayed in English.