Having talked this over with the other council members, it is unlikely that we will look at user guide translations as part of the framework itself - the user guide is too extensive, too variable, and there are too many languages.
We aren't discouraging such translations, but will probably only provide links to them, without endorsing them, perhaps on the CodeIgniter website.
In any case, talk about user guide translations for CodeIgniter4 is premature, as the structure and content is still far from finalized!