How to create more languages for users to change UI Backoffice CMS?

I am using version 13.2.2.

I installed it via Net Cli

dotnet new umbraco -n MyCustomUmbracoProject

How to add new Languages (languages that Umbraco doesn’t support)?


This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/114010-how-to-create-more-languages-for-users-to-change-ui-backoffice-cms