1. In the Location bar, type about:config and press Enter.
2. Find the "browser.fixup.alternate.enabled" setting in the list of preferences
3. Double-click the "browser.fixup.alternate.enabled" preference to change its value to "true/false".
To toggle the internet keyword search:
1. In the Location bar, type "about:config" and press Enter
2. Find the "keyword.enabled" preference in the list of preferences
3. Double-click the "keyword.enabled" preference to change its value to false/true.
To change the keyword search service, follow step 1.
2a. Find the "keyword.URL" preference
3a. Change the "keyword.URL" preference to "http://search.yahoo.com/search?p=" for yahoo or "http://www.bing.com/search?q=" for bing, or any other appropriate search URL for the corresponding search engine.
1. Browse to the website that you want to search.
2. Rightclick the search field that you want to use to search the website.
3. In the opening context window, select "Add a keyword search for this site"
4. In the opening window, in the Keyword field, enter a search prefix. Click OK.
5. To use the created smart bookmark, enter the keyword and the search string in the Location bar and then press Enter.
According to http://www.w3.org/International/questions/qa-lang-priorities this is simple:
Firefox
To change your language preferences go to Tools > Options (Windows) or Edit > Preferences
got to tab Content. Down right of Languages click on the button Choose.
* You can add languages to this from a (long) pre-defined set, and Firefox will send all the languages you choose with the Accept-Language header in the order in which you arrange them.
* You can't create custom language tags using the standard interface. (You can, however, via about:config, using intl.accept_languages if you are geeky enough.)
Safari
On Mac OS X the language sent is that specified in the OS X system language preferences. To change those preferences go to System Preferences > Language & text > Language. You can have a long list of languages in this dialog box, but Safari will only send the top item with the Accept-Language header. You can't create custom language tags.
On Windows, you can't change the language sent by Safari. The language sent with the Accept-Language header is derived from your system settings.
Google Chrome
To change your language preferences go to Options (Windows) or Chrome > Preferences (Mac OS X), and select Under the Bonnet > Web Content > Languages & Spellchecker settings.
You can add languages to this from a pre-defined set, and Chrome will send all the languages you choose with the Accept-Language header in the order in which you arrange them. You can't create custom language tags.
Opera
On Windows you can change your language preferences at Menu > Settings > Preferences > General > Language > Details (button).
First of all, you must install the Firefox add-on GreaseMonkey from the following link: https://addons.mozilla.org/de/firefox/addon/greasemonkey/. Next, you must restart your PC in order to activate the add-on. On this Page: http://userscripts.org/ , you can find many useful scripts in order to customize and enhance your browser experience. When you have find a script which you are interested in, just click on the install button, confirm the installation and you will find the scripts on the Firefox add-on page. There you can add/remove, activate/deactivate scripts and modify options.
You can find further information’s on how to create and modify scripts on the following Homepage: http://wiki.greasespot.net/Main_Page