[palves]

While I generally agree with the principles underlined in the article, using the Accept-Language header is definitely not the right way to control internationalization.

Remember that one of the advantages of URLs is the ability to easily share them, however I'm not sure I'd be comfortable sharing content that could show up translated to some recipients, based on the language of their browser/application/computer. For example, most CMS systems assume that the content can be completely different between languages (for the same article): you can have the full text in English and only a teaser in other languages.

Maybe not a pure REST approach but using '/en','/pt','/fr' in the URL has proven to be much easier and safer, from my experience.

[icebraining]

It depends on what content is translated. I think that Accept-Language is OK for UI elements - seeing 'entrar' instead of 'log in' and elements like that. For actual content, probably not.