W3C I18N Techniques: Authoring XHTML & HTML

Always declare the default language for text in the page using attributes on the html tag, unless the document contains content aimed at speakers of more than one language.

Where a document contains content aimed at speakers of more than one language, decide whether you want to declare one language in the html tag, or leave the languages undefined until later.

Where a document contains content aimed at speakers of more than one language, try to divide the document linguistically at the highest possible level, and declare the appropriate language for each of those divisions.

Use the lang and/or xml:lang attributes around text to indicate any changes in language.

For HTML use the lang attribute only, for XHTML 1.0 served as text/html use the lang and xml:lang attributes, and for XHTML served as XML use the xml:lang attribute only.

Use language attributes rather than HTTP or meta elements to declare the default language for text processing.

Do not declare the default language of a document in the body element, use the html element.

If the text in attribute values and element content is in different languages, consider using a nested approach.

Declaring Language in XHTML and HTML

W3C tutorial.

Using attributes to declare language

In W3C best practices document (Specifying Language in XHTML and HTML Content)

Declaring metadata about the language of the intended audience

In W3C best practices document (Specifying Language in XHTML and HTML Content)

Why use the language attribute?

Why use the language attribute? A number of useful reasons.

Specifying the language of content: the lang attribute

lang attribute definition in HTML 4.01 (in HTML 4.01 spec, section 8.1)

Language Identification

xml:lang attribute definition in XML 1.0. (in XML 1.0 spec, section 2.12)

Clarify natural language usage

Express natural language in a document. (in Web Content Accessibility Guidelines, Guideline 4)

Identifying changes in language

Use lang attribute when language changes in a document (in Web Content Accessibility Techniques for HTML, section 2.1)

Identifying the primary language

Use lang attribute on html tag (in Web Content Accessibility Techniques for HTML, section 2.2)

The lang and xml:lang Attributes

xml:lang and lang attribute definitions in XHTML 1.0 (section C.7)

Content-Language

Content-Language definition in HTTP 1.1 (section 14.12)

Specifying the language of content: the lang attribute

HTML on Content-Language, only says that the HTML language attribute has a higher precedence (in HTML 4.01 spec, section 8.1)

Automatic font assignment for CJK text

W3C test page

Automatic font assignment for CJK text

W3C test results

Language declarations

W3C test page

Document-level language declaration

W3C test results

Consider using a Content-Language declaration in the HTTP header or a meta tag to declare metadata about the language(s) of the intended audience of a document.

Where a document contains content aimed at speakers of more than one language, use Content-Language with a comma-separated list of language tags.

Declaring Language in XHTML and HTML

W3C tutorial.

Declaring metadata about the language of the intended audience

In W3C best practices document (Specifying Language in XHTML and HTML Content)

Using HTTP and meta for language information

Should I declare the language of my XHTML document using a language attribute, the Content-Language HTTP header, or a Content-Language meta element? W3C article.

Content-Language

Content-Language in the HTTP1.1 specification (section 14.12)

Specifying the language of content: the lang attribute

Content-Language in the HTML specification: only says that the html language attribute has a higher precedence (section 8.1)

Decide whether you want to declare one language in the html tag, or leave the languages undefined until later.

Try to divide the document linguistically at the highest possible level, and declare the appropriate language for each of those divisions.

Use Content-Language with a comma-separated list of language tags.

Mechanisms for declaring language in HTML

In W3C best practices document (Specifying Language in XHTML and HTML Content)

Declaring Language in XHTML and HTML

W3C tutorial.

Why use the language attribute?

A number of useful reasons. W3C article.

Using HTTP and meta for language information

Should I declare the language of my XHTML document using a language attribute, the Content-Language HTTP header, or a Content-Language meta element? W3C article.

Content-Language

Content-Language in the HTTP1.1 specification (section 14.12)

Follow the guidelines in the IETF's BCP 47 for language attribute values.

Use the shortest possible language tag values.

Where possible, use the codes zh-Hans and zh-Hant to refer to Simplified and Traditional Chinese, respectively.

How to choose language values

W3C best practices document (Specifying Language in XHTML and HTML Content)

Language tags in HTML and XML

How to choose the right attribute values. W3C article.

Specifying language tag values

W3C tutorial (Declaring Language in XHTML and HTML)

Language Subtag Registry

IANA's language tag registry.

Language Subtag Registry search tool

User friendly interface to IANA's language tag registry by Richard Ishida.

Internet-Draft: BCP 47

Points to a document containing both RFC 4646 (Tags for the Identification of Languages) and RFC 4647 (Matching Language Tags)

RFC 4646 Tags for the Identification of Languages

The specification.

RFC 4647 Matching of Language Tags

The specification.

Understanding the New Language Tags

Overview of RFC3066bis by one of its authors. W3C article.

Specifying the language of content: the lang attribute

lang in the HTML 4.01 spec (section 8.1)

Language Identification

xml:lang in the XML spec (section 2.12)

Two-letter or three-letter language codes

Should I use two-letter or three-letter ISO language codes in language tags? W3C article.

RFC 3066 Tags for the Identification of Languages

The previous IETF document that used to define how to use language tags to identify languages, now obsolete.

ISO 3166: Codes for Country Names

ISO country codes

ISO 639: Codes for the Representation of Names of Languages

ISO language codes

Automatic font assignment for CJK text

W3C test page

Automatic font assignment for CJK text

W3C test results

Use the lang and/or xml:lang attributes around text to indicate any changes in language.

For HTML use the lang attribute only, for XHTML 1.0 served as text/html use the lang and xml:lang attributes, and for XHTML served as XML use the xml:lang attribute only.

Using attributes to declare language

In W3C best practices document (Specifying Language in XHTML and HTML Content)

Declaring Language in XHTML and HTML

W3C tutorial.

Declaring metadata about the language of the intended audience

In W3C best practices document (Specifying Language in XHTML and HTML Content)

Why use the language attribute?

Why use the language attribute? A number of useful reasons.

Specifying the language of content: the lang attribute

lang attribute definition in HTML 4.01 (in HTML 4.01 spec, section 8.1)

Language Identification

xml:lang attribute definition in XML 1.0. (in XML 1.0 spec, section 2.12)

Clarify natural language usage

Express natural language in a document. (in Web Content Accessibility Guidelines, Guideline 4)

Identifying changes in language

Use lang attribute when language changes in a document (in Web Content Accessibility Techniques for HTML, section 2.1)

The lang and xml:lang Attributes

xml:lang and lang attribute definitions in XHTML 1.0 (section C.7)

When pointing to a resource in another language, consider the pros and cons of indicating the language of the target document.

If you want to indicate that the target document of an a element is in another language, consider the pros and cons of using hreflang with CSS.

Do not use flag icons to indicate languages.

How to indicate the language of a link destination

W3C best practices document (Specifying Language in XHTML & HTML Content)

The :before and :after pseudo-elements

:before and :after in the CSS 2.1 spec (section 12.1)

The A element

hreflang in the HTML spec (section 12.2)

Hreflang content generation

W3C test page

Hreflang content generation

W3C test results

Styling using the lang attribute

Compares :lang, lang |= and lang= selectors, and assesses current usability (W3C article)

The language pseudo-class :lang

CSS2 Specification (section 5.11.4)

Attribute selectors

CSS2 Specification (section 5.8)

Class selectors

CSS2 Specification (section 5.8.3)

ID selectors

CSS2 Specification (section 5.9)

Language dependent styling

W3C test page

Language dependent styling

W3C test results