Is there ever going to be japanese added to this site? I already know some basic stuff but its hard to find anything that helps with more advanced stuff.
Is there ever going to be japanese added to this site?
One day, yes.
But Duo needs to tackle some issues (related to the script) first to be able to have courses teaching it. See here for an official statement about that.
If you want to make a [course] suggestion, we encourage you to visit the forums and making a search for suggestions that have been made in the past, and adding your vote and comments to those existing posts [and thus not creating a new one]. That will make the request more popular and make it stand out more, encouraging more people to add their votes. :)
Note: Texts in between square brackets are additions of mine.
And the guide linked above does have a link for an existing suggestion made in the past about the course you're suggesting.