Default language

The default language of a web page is the primary language in which its content is written. It is declared in HTML with the lang attribute on the document's root element. Without this declaration, screen readers do not know which pronunciation rules to apply and read the text with the accent of the language configured on the user's system.

A French website without lang="fr" on its <html> tag. The screen reader reads all content using the phonetic rules of the language configured on the user's system. Every French word, pronounced like English.

#What the lang attribute does

The lang attribute on <html> tells browsers and assistive technologies what language the content is written in. When a screen reader like NVDA or VoiceOver encounters lang="fr", it loads French pronunciation rules. Braille displays apply the corresponding contraction tables. On the browser side, this attribute determines the quotation marks for <q>, the date format in input fields, and the language for spell-checking.

The implementation comes down to a single attribute:

<html lang="fr">

The code uses the BCP 47 standard: fr for French, en for English, de for German.

#A level A criterion, always overlooked

WCAG criterion 3.1.1 requires that the default language of each page be determinable programmatically. Level A: the bare minimum. RGAA restates this requirement in criteria 8.3 and 8.4.

The absence of a declared language ranks among the 6 most frequent errors detected by WebAIM Million 2025 across one million home pages.

#The error nobody sees

Putting lang on <body> instead of <html>. The <head> is not covered. Yet the page's <title>, often the first element read by a screen reader, is located in the <head>.

<!-- ❌ Does not cover the <head> -->
<html>
  <head><title>My site</title></head>
  <body lang="fr">...</body>
</html>
 
<!-- ✅ Covers the entire document -->
<html lang="fr">
  <head><title>My site</title></head>
  <body>...</body>
</html>

Another pitfall: language codes are not country codes. Luxembourgish is lb, not lu (which designates Luba-Katanga). And fr-FR is useful only to distinguish French from France from French from Canada (fr-CA). For most websites, fr is sufficient.

#In summary

Add lang to <html>, not to <body>. Use a valid BCP 47 code. One line of code, a level A criterion, and one of the quickest accessibility fixes to deploy.

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Language Change

A language change is a word or passage written in a language different from the main language of the page. In HTML, it is marked with the lang attribute on the element containing this text. Without this markup, screen readers pronounce the foreign text with the accent of the main language.

Page Title

The page title is the content of the HTML <title> tag, displayed in the browser tab. It is the first information a screen reader announces when opening a page. WCAG criterion 2.4.2 (level A) requires that each page has a title describing its subject or function.

Document structure

Document structure is the logical organization of a web page through hierarchical headings (h1 to h6) and semantic HTML5 tags. Screen readers use them to build a navigable table of contents and allow their users to jump directly to the desired section.