How does Google determine the page language?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Collins Opara: You have nothing to worry if you use Google translate.
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  Richard Hearne: Collins Opara I suggest you go away and test a few pages with Google Translate content. You`ll find pretty quickly that Google will get bored. Bottom line: Google does not want you publishing content via Google Translate. Use Google Translate to translate, but don`t republish those translations.
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  Collins Opara: Richard Hearne Of course I wasn`t talking about publishing the translated version, just for the translation purpose, still go ahead and target your keywords.
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  Richard Hearne: Yeah, I think the OP is asking about published content.
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  Richard Hearne: You could write a large paper in response to all these questions. I`ll try to answer a bit. My replies are based on working with enterprise sites across 20 or more langs.> Will Google automatically direct them to their local language or native language?Yes> Is it based on location? Browser`s language? OS language?First 2, and probably some other factors which you wont need to concern yourself about.> How does Google determine?Logged in user settings, browser accept langs, user location, Google ccTLD etc.> Will it be automatically redirected if Inused hreflang tags?HREFLANG is a signal you can provide which helps Google to understand different translations of the same piece of content. They will then swap in a more appropriate language for the searcher if your page ranks.> Should I use a canonical tag in order to connect the translated pages to the original page?No. There are some edge cases where you could do so (same Lang), but don`t try this as you`re clearly a beginner. Each language page needs to self-canonicalise.> If I won`t use an hreflang tag or a canonical tag, will Google not know that these pages are connected?If your site architecture is good then you should not be at a disadvantage. Canonical tags only really help when you present mixed signals. HREFLANG tags can give you a small advantage, but not absolutely necessary.> Will Google not redirect?I`ve no idea what the question is here. Google doesn`t redirect anything.> What about the PageRank? Will each version have it`s own PR in different scenarios or only if it is done without both tags?You`re getting too deep now. This shouldn`t matter to you. The answer is each canonical URL will have it`s own PR. Canonical tags can affect this. HREFLANG does not affect PR. It is simply a signal which Google CAN (not WILL) use to swap in an appropriate Lang version of a page in their search results.