how can i change the language of OS X Lion from english to any language?

System Preferences > Language & Text > Language. You will have to restart any running applications for them to pick up the new language. For applications such as the Finder, that means a Dock relaunch or logout.

Syatem Preferences/Language and Text if your choice is not there click the Edit List button at the bottom

Khaled Gad wrote:

i changed the language to arabic

Did you put Arabic at the top of the list in system prefs/language & text/language and then logout/login?

The most you should ever have to do is log out and back in.

Try creating a new account, logging in to that, and change the language in that account to Arabic. I just tried that and it worked fine. If that works for you, then there is some problem with the old account. If you migrated it from an older installation, it may not have moved over well.

Just had the same problem. Here is my solution:

- the user you create and use to administer Lion Server is still inferior to root.

- in order to change the system language, log in as 'root' and then change the language in System Preferences

Hope this helps

LL

PS: just realised, there is still one step missing...

Here is the solution of changing the language of the Login Screen:

I just found the answer in this post: http://support.apple.com/kb/HT4102

Essentially login with an admin account, open terminal and perform sudo languagesetup

It then lets you choose the default login language!

<Edited by Host>

LL

Will the dictionary also change language?

If you are talking about Dictionary.app, that only comes in English and Japanese.

If you are talking about spell checking, that is regulated via system prefs/language & text/text/spelling