Supported languages for Ad Exchange ad serving
Ad Exchange supports publishers in several different languages. You can select your site's primary language during the application process. If you're approved, Ad Exchange will serve relevant ads to your pages in the appropriate language, even if your site contains multiple supported languages.
When targeting languages, make sure your demand sources also support those languages. For example, if you target "English (Canada)", only demand sources that support that specific form of English will be able to bid on your inventory.