Ad targeting by language
Our technology can determine the primary language of a page. If your content is in a language supported by our program, AdSense will target ads in the appropriate language to your content. We also target ads to match the language settings specified by advertisers in their advertising campaigns. Language targeting allows advertisers to choose the language of the sites that they'd like their ads to appear on.
In addition, we may look at the language of the pages a user is viewing or has recently viewed to determine which ads to show. This means that we may detect the language from either pages that the person had viewed in the past, or the page that they are currently viewing. In this case, AdSense may target ads in the user's detected language rather than in the language of your content.