Forum Moderators: martinibuster
If your site is mixed language they will attempt to show the language of that actual page.
Also note that it might show a different language for different people based on country or browser language. I'm not sure about this.
If the problem doesn't fix itself, you can contact google support, and they will give you a new line for your adsense code to override the automatic language selection. If you do this, they state that the language you choose must match the main language of that page.
I have a mixed language site, and adding this line of code has fixed all problems.
Then there are advertisers who buy domain wide ads in a language and you will always see them even though they are useless to a reader.