That’s not possible. Mostly because a translation is something where the only use is “what is THIS_STRING in LANGUAGE-X”. You could though take your i18n files, create a toml file in data for all the labels and then iterate through site.Data.tomlfilefori18n and read the terms from the translation files in. Lots of work if your translations change often.
That is “hacky”, but ranging through translation terms is hacky if their task is to translate, not to list.
I’m settle with following way which I experimented and worked like a charm:
Instead of i18n files I simply made use of page front matter. I simply created _index.md and _index.de.md and used front matter.
It’s even better because we use only one file for translation.