I understand if the existing editors can't personally proofread the submissions, but that's why peer-review exists. Or an open-source project in general where people can post corrections. Jimbo Wales didn't need to speak a hundred languages to launch Wikipedia.
To me, that niche is already covered by Wikisource. Standard Ebooks as a project is very strict about conforming to its editorial and quality standards. On boarding more languages would require volunteer editorial experts in those languages.
Besides, projects in other languages can absolutely build upon Standard Ebooks work, but to expect Standard Ebooks itself to support other languages is just too outside the scope and expertise of the volunteers available.
If you were to find the expert editors for the other languages would you let them publish the works in those other languages on standards books website?
well, that would be up to Alex. but as that would require a pretty substantial organizational and responsibility shift, I imagine, no, he would not.
As it is now, Alex is editorially responsible for all output of Standard Ebooks. Changing that would require someone with the time and experience willing to take on all the responsibilities that Alex currently has for each of those other languages.
A well-defined focus can help management of a project, for example, by not having the participants spread too thin.
The website and toolchain are open source, so if someone would build an international version, and do it persistently, I'm sure they would link or maybe even merge the projects a bit.
I understand if the existing editors can't personally proofread the submissions, but that's why peer-review exists. Or an open-source project in general where people can post corrections. Jimbo Wales didn't need to speak a hundred languages to launch Wikipedia.