AdSense technology can determine the primary language of a page. If your content is in a language supported by AdSense program , AdSense will target ads in the appropriate language to your content.
AdSense 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.
A person who views Google Display Network (GDN) content in Thai may see ads from campaigns targeted to Thai. Also, someone whose Google language is set to Spanish can see ads from advertising campaigns targeted to Spanish.
In addition, AdSense 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 AdSense 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.
Maya has viewed several cooking blogs on the GDN that are written in Japanese, and she sees ads from campaigns targeted to Japanese speakers. She may also see Japanese ads even when she reads other blogs on the GDN that are written in English.