It has been asked before.
The short version, choicescript and CoG does not support the writing of games in other languages.
Even if you wrote all the content in another language, the “Next” button at choice sections and other options would still be in English. If you are tech savvy enough to modify the innards of the choicescript engine, it could possibly be changed, but it would be unsupported, and you would be better off using a different game engine like ren’py with localization support.
If you plan to submit the game to HG:
That is out. CoG/HG will only accept submissions in English, and to the best of my knowledge, they have not changed this position or gave any indication that they would do so.
If you plan to make a hobby game:
You’ll still have the issues I mentioned earlier. Not to mention, getting support on this forum will be difficult as not everyone here may be able to read said language.