https://www.arduino.cc/en/Main/Documentation is a super outdated page that I don't think is linked to from any other page on this website so there would be no benefit in translating it to other languages. Better would be for them to just delete that page.
Work is currently being done to translate the Language reference pages:
Including all the pages linked from that page, but not yet the Libraries pages or the Glossary.
Currently this is happening for the following languages:
which don't include Korean.
If you are willing to do a significant amount of work toward translating all the Language Reference content to Korean I recommend as the first step to make a proposal in an issue report here:
Make sure to clearly state the level of commitment you are willing to make to the project as that could be a significant factor in the Arduino team's decision on whether to go ahead with your proposal.
I think this would be a very valuable contribution to the Arduino project.
You may already be aware, but there is also a Korean translation of the Arduino IDE. If you find any improvements that may be made to that translation you are welcome to contribute them here: