Quoted from Google AdSense help:

You can select your site's primary language during the application process. If you're approved, AdSense will serve relevant ads to your pages in the appropriate language, even if your site contains multiple supported languages.

Please also be aware that placing the AdSense code on pages with content primarily in an unsupported language is not permitted by the AdSense program policies.

Unfortunately Indonesian language has not yet been supported until today while I consider to use AdSense for my blogs.