[questions/qa-html-language-declarations] Declaring language in HTML in important for accessibility

[xfq]

[source] (https://www.w3.org/International/questions/qa-html-language-declarations) [en]

Declaring the page language is required by WCAG Success Criterion 3.1.1 to help assistive technologies like screen readers pronounce content correctly. When content in different languages appears within a page, those parts must also be identified (WCAG Success Criterion 3.1.2). I think it is necessary to mention this to help readers understand the importance of the lang attribute. Although we already have an article specifically discussing why we need to add language attributes, since WCAG is a very important standard, I think it is still worth mentioning.