Hreflang is one of the attributes that can be specified in the HTML Link tag or A tag, and the target HTML language can be specified. In the case of a Link tag, this specified attribute, generally called the Hreflang annotation , can notify the URL of the alternative HTML in the Hreflang specified language of the currently displayed document. You can specify the language in which is written.
In Hreflang, you can specify two types of combination of language and region. For example, if you write nl-be, the region is Belgian language is Dutch, and if you write fr-be, the region is Belgian language. Is in French.
The main use is to translate the content into multiple languages and create pages for each. In this case, if the domain is ccTLD , Google may set the ccTLD language by default (with exception). , In that case, unless the Hreflang setting is used, the language of the corresponding web page may not be recognized correctly.