Part of my CI/CD is a script that makes builds fail if any of my languages are missing keys, it takes English as the desired result and checks all the keys to ensure they all exist and prints a report of the ones that are missing in csv format so I can send them to translators. I generally run this manually before committing, but having it in the CI/CD helps preventing these errors from making it into production…
You usually can install plugins (it’s been a long time since I looked into it, so the situation might have changed) to have support for other languages and “convert” it, but doesn’t work as good as their standalone versions as they are a bit more integrated and better configured out of the box imo