The value of the lang
attribute must be a valid BCP 47 language tag or the empty string (if the language is unknown).
The BCP 47 language tags are listed in the IANA Language Subtag Registry.
The relevant WCAG 2.0 Success Criteria are:
The related WCAG 2.0 Techniques are:
It’s a good practice to declare the primary language of the document in the html
element:
<html lang="en">
If no other lang
attribute is specified in the document, it means that everything (i.e., element content and attribute text values) is in that language.
If the document contains parts in other languages, these parts should get their own lang
attributes to "overwrite" the language declaration.
The lang
attribute is used to specify the language of element content and attribute text values:
<p lang="en">The content of this element is in English.</p>
<p lang="en" title="The value of this attribute is also in English.">The content of this element is in English.</p>
The language declaration gets inherited:
<div lang="en">
<p>This element contains English content.</p>
<p title="This attribute, too.">Same with this element.</p>
</div>
You can "overwrite" a language declaration:
<p lang="en">This English sentence contains the German word <span lang="de">Hallo</span>.</p>
You can "overwrite" a parent element's language declaration by introducing any element apart from applet
, base
, basefont
, br
, frame
, frameset
, hr
, iframe
, meta
, param
, script
(of HTML 4.0) with an own lang
attribute:
<p lang="en" title="An English paragraph">
<span lang="de" title="A German sentence">Hallo Welt!</span>
</p>
It is possible to add the attribute hreflang
to the elements <a>
and <area>
that create hyperlinks. Such it specifies the language of the linked resource. The language defined must be a valid BCP 47[1] language tag.
<p>
<a href="example.org" hreflang="en">example.org</a> is one of IANA's example domains.
</p>
<element lang="language_code">
<!-- Language code has to be in the format [ISO 639-1](https://en.wikipedia.org/wiki/ISO_639-1 ) -->