Mixed-language pages can be confusing to Google
In general, Google tries to use the primary content of a page to determine which language a page is targeting. However, it’s also recommended to make title tags and headings match the page’s primary language. Having various elements on one page in different languages makes it hard for Google to know how the page should appear in the index.
You can ask Google not to translate your pages with a “notranslate” meta tag
Google’s translation feature aims to make your content accessible to a larger group of users, but there may be scenarios where you’d prefer pages not to be translated. It’s possible to prevent titles and snippets from being translated in search engine results pages with the “notranslate” meta tag. This signals to Google that a translation for that page is not required and will also stop users from being shown the ‘Translate this page’ prompt when they open a URL.
Language is evaluated on a per-page basis for SEO
Does an entire website need to be translated to rank well in an alternate language? John responded to a question about whether it would be ok to only translate some pages in a website rather than the entire site. He answered that language is looked at on a per-page basis, rather than evaluating whole parts of a website, so this approach would be fine. He recommended making sure that internal linking is in place to these translated pages so that they can be found.
Google Tries to Detect User’s Language Preferences if Using Default Version of Chrome
Google is aware that sometimes users download the default version of Chrome in English rather than their preferred language, and will try to detect this and show the correct language versions of pages to help with localization.
You Can Publish Different Language Variations of Content Without Using Subdomains or Subdirectories
Content in different language variations should be on different URLs, but it doesn’t necessarily need to be put on subdirectories or subdomains. For example, this could be achieved with different parameters.
Only One Version of Same Content On Different Country Sites will be Indexed & Appear in GSC Performance Reports
If you have the same content on multiple language variation sites, Google will pick one to index but will use hreflang attributes to swap out versions of the page based on a user’s location. However, only the page that has been chosen to be indexed, and used as the canonical, will be displayed in the GSC performance report.
Translated Content is Treated as a Completely New Piece of Content
Content that has been translated by a translator is treated as unique content and not seen as spun content, this is because the words are different when translated from one language to another.
Both ccTLDs and GSC Geo-targeting are Equivalent Methods of Country Targeting
When determining a country to target, John recommends two main methods. The first is using a ccTLD, the other is using a generic TLD and specifyng the geo-targeting in GSC. Both of these methods are equivalent and used by Google to determine language targeting for websites.
Adding New Language Versions Alongside Migration Can Delay Processing
For Google to be able to process site migrations quickly, they need to be one-to-one moves. Adding new language versions alongside a migration means Google will need to process each of these versions separately which will take longer.