# The lang attribute must have a valid value on all elements. > Canonical HTML version: https://rocketvalidator.com/accessibility-validation/accesslint/0.16/readable/valid-lang > Attribution: Rocket Validator (https://rocketvalidator.com) > License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) When a page contains text in a language different from the document's primary language, the `lang` attribute on the wrapping element tells assistive technologies which language rules to apply. If the value of that `lang` attribute is not a valid BCP 47 language tag, screen readers cannot switch to the correct pronunciation and inflection. The result is garbled or misleading speech output for users who rely on screen readers. For example, a French quotation inside an English page should be wrapped in an element with `lang="fr"`. If the attribute instead contains a typo like `lang="fren"` or an invented code like `lang="xyz"`, the screen reader has no way to identify the language. It will either read the text with English pronunciation rules or fall back to unpredictable behavior depending on the assistive technology. This rule applies to any HTML element inside `` that has a non-empty `lang` attribute and contains human-language text. The primary language subtag in the value must be recognized — meaning it must be a valid subtag registered in the IANA Language Subtag Registry. Region subtags (like `CH` in `fr-CH`) and other subtags after the primary tag are not checked by this rule; only the primary language subtag matters. ## Which users are affected Screen reader users are the most directly affected. Screen readers like JAWS, NVDA, and VoiceOver use the `lang` attribute to load the correct text-to-speech voice and pronunciation dictionary. An invalid language tag prevents the correct voice from loading, so the text is read with the wrong pronunciation. This can make content unintelligible. Users of braille displays are also affected, since the `lang` attribute determines which braille translation table is used. ## Related WCAG success criteria This rule maps to [WCAG 2 Success Criterion 3.1.2: Language of Parts](https://www.w3.org/WAI/WCAG22/Understanding/language-of-parts.html) (Level AA). SC 3.1.2 requires that the human language of each passage or phrase in the content can be programmatically determined. A `lang` attribute with an invalid value fails to meet this requirement because assistive technologies cannot determine the language from it. ## How to fix it 1. Identify every element that has a `lang` attribute. 2. Check that the value starts with a valid primary language subtag. Common valid subtags include `en`, `es`, `fr`, `de`, `zh`, `ja`, `pt`, `ar`, `ru`, `ko`, `it`, `nl`, `hi`, and `sv`. 3. Replace any invalid or misspelled subtag with the correct BCP 47 code. You can look up codes in the [IANA Language Subtag Registry](https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry). 4. If the element does not actually contain text in a different human language (for example, a `

` element where `lang` was mistakenly used to indicate a programming language), remove the `lang` attribute entirely.

Region and script subtags after the primary subtag are optional. `lang="fr"` and `lang="fr-CA"` are both valid. The primary subtag is what matters for this rule.

## Examples

### Invalid language tag

The `lang` attribute has a value that is not a recognized language subtag:

```html

  
    
      Ils ont trouvé un étrange bar Tiki aux abords de la petite ville balnéaire.
    
  

```

`fren` is not a valid BCP 47 primary language subtag. A screen reader cannot determine the language and will likely read this French text using English pronunciation.

### Valid language tag

Use the correct two-letter (or sometimes three-letter) subtag:

```html

  
    
      Ils ont trouvé un étrange bar Tiki aux abords de la petite ville balnéaire.
    
  

```

`fr` is a valid subtag for French. The screen reader can switch to a French voice for this paragraph.

### Valid language tag with region subtag

Region subtags are allowed and do not cause failures:

```html

  
    
      Ils ont trouvé un étrange bar Tiki aux abords de la petite ville balnéaire.
    
  

```

`fr-CH` identifies Swiss French. The primary subtag `fr` is valid, so this passes the rule. Even if the region subtag were syntactically unusual, the rule only checks the primary subtag.

### Empty lang attribute (not flagged by this rule)

```html

  
    Bonjour
  

```

An empty `lang` attribute is outside the scope of this rule because the value is empty. However, an empty `lang` value has its own meaning in HTML (it indicates that the language is unknown) and may be flagged by other rules.