You may have noticed when creating a new AdWords campaign that Google sometimes suggest targeting multiple languages based on the location that you've targeted. To help you understand why Google make those recommendations, here's a refresher in how language targeting works today:
- Refresher: Campaigns that target a language are targeting the interface language that a user has set as the language in which they'd like the Google interface to be displayed. A Spanish-speaker living in the US, for instance, may want to perform searches on www.google.com but change the interface language setting to Spanish. Alternatively, an English-speaker living in Japan may want to perform searches on www.google.co.jp but see an English interface.
Currently, your ad appears only when UI language matches the targeted language. This means that your ad won't necessarily appear when a user searches for a keyword in the language that you're targeting, if the UI is in another language.
- New improvement: Determining the language of the search from the query itself can sometimes be difficult, since some words are common to more than one language. However, there're five languages in AdWords that can be uniquely identified by their characters: Greek, Hebrew, portions of Japanese, Korean, and Thai. Therefore, starting in late April, if you're targeting any of these five languages, your ad will be eligible to show for all queries in that language that match your keywords, regardless of the user's interface language (your location targeting settings will still apply).
While targeting multiple interface languages will continue to be the best way for many of you to maximize the amount of traffic that your campaigns receive, Google will continue to look for new opportunities to improve our language targeting offering.
More Info: FAQ