Add Localization Module

Hello!
Our goal is to enable users to login to the /cms backend, and be able to select “Japanese” as their language. This would enable CMS users to see labels presented in Japanese.

Referencing this article: Configure the CMS Login Page - Bloomreach Experience Manager (PaaS/Self-Hosted) - The Fast and Flexible Headless CMS

I am understanding that you can enable languages for:

English, French, German, Dutch and (simplified) Chinese

What I am looking for is instructions on how to create or enable a localization module for Japanese.

We are specifically looking for help localizing the CMS interface. We do understand how to localize CMS component labels.

Please help!