As of 2015, Google understands the browser language redirection and will interpret it as a redirect to another URL. Google may index your site from multiple IP addresses and resolve the language redirect rules, but there is no guarantee to how this redirect affects your site’s indexing. This is related to how Google works and not to how the language redirect is implemented in WPML. If you see the ‘wrong’ languages in Google index, consider disabling the browser language redirection.
A: Don’t do this. Google is very consistent about its instructions about indexing. You must allow GoogleBot to index your site exactly like visitors see it. Avoid what Google calls sneaky redirects.
A: It’s impossible to tell, because nobody knows exactly how Google will respond. You should use Google Webmaster Tools to see how Google indexed your site. If you suspect that your content is indexed in the wrong language, it’s a good idea to disable the browser redirect. Google frequently updates their crawling and indexing algorithms. What works now may not work later and what fails now may work in the future. In any case, it’s a good idea to periodically review your index status and respond to alerts coming from Google Webmaster Tools.
Q: I want to offer the ‘correct’ content to my visitors. Any good alternatives to browser language redirect?
Placing a language switcher, with flags and with native language names, in a prominent position on your pages is the best way to show people that you have content in their language. WPML offers a number of language switchers for you to use and you can also create custom language switchers. If you want to first ask people about their language or region and then show relevant content, you can enable language directory for the default language and then place a welcome page in the site’s root.