CSS font-language-override

The font-language-override property allows you to control the use of language-specific glyph substitutions and positioning.

The font-language-override property is one of the properties introduced in CSS3 for enabling various font related features that can improve the appearance of the text on the page. The font-language-override property deals specifically with language-specific glyph substitutions and positioning. It allows you to override the language system used by the content language.

This property can be useful in certain cases because, many languages share a common script, but the shape of certain letters can vary across those languages, depending on their context. For example, in Latin text, many fonts render "fi" with an explicit fi-ligature that joins the two glphs into one, and removes the dot from the "i" (example. However, in languages such as Turkish a dotted-i has a different meaning to a dotless-i. So generating such a ligature is not a good option in this case. Therefore, you would either want to use a specialized ligature that maintains the dot over the "i", or avoid the ligature altogether.


The syntax of the font-language-override property is:

Possible Values

Specifies that when rendering with OpenType fonts, the content language of the element is used to infer the OpenType language system.
This value is a single three-letter case-sensitive OpenType language system tag that specifies the OpenType language system to be used instead of the language system implied by the language of the element.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

Represents the value specified as the property's initial value.
Represents the computed value of the property on the element's parent.
This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

General Information

Initial Value
Applies To
All elements

Example Code

An HTML document might use the following code to indicate that the language is Macedonian:

However, the font might not support the typographic conventions of this language. Therefore, you could use the font-language-override property to specify a language that the font does support.

So if the font supports Serbian for example, you could do this in your CSS:

Official Specifications

Vendor Prefixes

For maximum browser compatibility many web developers add browser-specific properties by using extensions such as -webkit- for Safari, Google Chrome, and Opera (newer versions), -ms- for Internet Explorer, -moz- for Firefox, -o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.

This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.

The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.

Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.

You can also use Autoprefixer with preprocessors such as Less and Sass.