If your website is available in multiple languages, it is usually a good idea to use the hreflang attribute to show Google the different language versions of your website. Unfortunately, incorrectly implemented hreflang attributes can lead to ranking problems.
Google’s John Mueller confirmed on Twitter that Google is usually able to figure out different languages without the hreflang attribute on the web pages:
If it's in a different language, usually Google can figure that out without hreflang. Most queries are clearly in one language, so we can send users to that version of the page.— John ☆.o(≧▽≦)o.☆ (@JohnMu) 26. April 2018
Google does not use hreflang as an authority signal
In another tweet, John Mueller said that the hreflang attribute is just a basic technical element, and they Google does not use it as an authority signal:
hreflang isn't an authority signal. It's a pretty basic technical element that not all sites need. No conspiracy here :-).— John ☆.o(≧▽≦)o.☆ (@JohnMu) 26. April 2018
Check your web pages for the hreflang attribute
Among many other things, the SEO website audit tool in SEOprofiler also checks your web pages for hreflang attributes. The SEO website audit tool helps you to improve your pages so that they can get better rankings on Google and other search engines. If you haven’t done it yet, create your free SEOprofiler account now: