FAQ: Setting language preferences in a browser

How do I check or change the language settings of my browser?

Specifying alternatives

You can specify several alternatives that will be treated in order of preference. The following example shows a setting in Internet Explorer 6 for someone who would prefer Swiss French pages, but if that is not available would settle for any French, German or English page, in that order.

Most browsers will allow you to select the languages you want from a list. You may also be able to specify custom language preferences. If you do so, you need to use values that will be recognized by the server (see below).

Your preferences should always be ordered from most to least specific, top to bottom. This generally means, if you use multiple subtags then include shorter tags lower down the list.

Important. Some of the server-side language selection mechanisms require an exact match to the Accept-Language header. If a document on the server is tagged as fr (French) then a request for a document matching fr-CH (French as spoken in Switzerland) will fail.

To ensure success you should configure your browser to request both fr-CH and fr, in that order. (See the example in the picture above.) This will cause the server to look for a Swiss French version first, but failing that, look for a French version.

Finding and using custom tags

Your language tag must start with a two- or three-letter code, called a subtag, from the list of languages specified in the IANA Language Subtag Registry. You may then add a second subtag to indicate a country or region, if you wish. These subtags can also be found in the registry. The first and second subtags must be separated by a hyphen.

Language. The IANA Language Subtag Registry is a long text file. To find a language subtag, search for the name of that language, in English. If we search for 'French', we find a record that looks like this:

Type: language
Subtag: fr
Description: French
Added: 2005-10-16
Suppress-Script: Latn

Note that the type of this record is 'language'. You use the code nearby that is labelled 'Subtag', ie. 'fr'.

Region. If you want to add a region subtag, such as CA for fr-CA (French as spoken in Canada), search for the name of the country or region. If you search for 'Canada' you will find a record like this:

Type: region
Subtag: CA
Description: Canada
Added: 2005-10-16

Note that this is a subtag of type 'region', which is what you want. Use the 'CA' subtag (to end up with fr-CA).

Subtags to avoid. You should avoid subtags that are described in the registry as redundant or deprecated. There are other types of subtag available in the registry, but, generally speaking, it is very unlikely that you would need to use them currently for this purpose (because people are unlikely to use the other subtags to label documents on the server).

Chinese. The registry also contains subtags for scripts, but these are not normally needed, and so should be avoided. One exception is the script tag for Chinese.

Chinese people, though they may speak mutually unintelligible dialects or languages, typically write what they want to say in the same way, distinguishing only between Simplified and Traditional forms of Chinese characters. If you are looking for Chinese information, therefore, you may want to simply specify whether the text is in simplified or traditional script, rather than in a specific language.

Due to the absence in the past of a way to refer to script in language subtags, servers tended to return text in traditional script if your language setting said zh-TW (Chinese as spoken in Taiwan), and in simplified script if your settings said zh-CN (Chinese as spoken in Mainland China). If your settings said zh-SG (Chinese as spoken in Singapore) or zh-HK (Chinese as spoken in Hong Kong), it is less clear that you will get back what you expect (normally simplified and traditional Chinese, respectively).

The IANA registry now also contains subtags for scripts. The Hans and Hant script tags in the registry allow you to specify preferences for zh-Hans (simplified Chinese) or zh-Hant (traditional Chinese).

It may be worth doing this, as people begin to label their resources using these tags on the server. However, you should also include other alternatives, to catch older servers that still use the old approach. For example, if you are living in Taiwan you may want to set up a list of preferences as follows:

zh-Hant
zh-TW
zh

Note that you should probably avoid using script tags for other languages in browser settings, though if you do, you should use them only as with alternative language tags - not in the only item in your preferences.

IE7

The values sent in the Accept-Language request-header from IE7 are typically of the form language-region. There is typically no language-only form. For example, if you are French your Accept-Language header will present fr-FR to the server.

There are some servers that are unable to match fr-FR against a document labelled on the server as fr. To avoid missing out on French resources from such sites you may want to add the fr as an alternative preference (after the fr-FR). You can do this by clicking on the 'Add' button in the language preferences dialog, and typing fr into the 'Custom' field.