The server generates status and error messages for the front end and is also responsible for sending text messages. These should be available in the same languages as the front end. So there are several tasks:
[x] Pass information back to the server on the currently selected language
[x] Add multi-language support (probably again i18next) to the server (use i18next-http-middleware)
[x] Add a preferred-language column to each subscriber and set based on language selected at the time the subscription was created.
[x] Change all hard-coded user-facing strings to use the translation function based on the selected language
[x] Set up language files for en, es, and ru. Spanish and Russian should just be the English prefixed by [es] or [ru] so we can get them translated.
Feature Request
The server generates status and error messages for the front end and is also responsible for sending text messages. These should be available in the same languages as the front end. So there are several tasks: