Hide text Externally from the URL

Dear All,
I am new to Apache, We are using CMS system. By default we are getting CMS URL pattern is like http:// <domain>/sites/<sitename>/<local-value>/<contents or campaign name>

• Here sites is context name of the WebApplication
• sitename is name of the Site which we given while create site in CMS.
• locale-value by default it will come en_US for English, ar_SA for Arabic

Ours is Multilingual site and using English & Arabic Contents. So, We want to change the name ar_SA to ar only, and dont want to display en_US from the URL.

So, I tried below Rewrite Rule, I think this rule applied for both internal & externally. So, It's changing the URL in Client-Browser, but getting 404 error page.

RewriteEngine on
#English
RedirectMatch "^/sites/ar_SA/(.*)" "/sites/ar/$1"
RewriteRule ^/sites/ar_SA/(.*) /sites/ar/$1 [L]

#Arabic
RewriteRule "^/sites/en_US$" "/sites/$1" [R]
RewriteRule "^/sites/(.*)$" "/qu/" [R]

Code (markup):

Please help me to resolve this issue.
Thanks
Jayaram

 

Shouldn't this be just:
RewriteEngine on
#English
RewriteRule ^/sites/<sitename>/en_US/(.*) /sites/$1 [L, QSA]
RewriteRule ^/sites/<sitename>/ar_SA/(.*) /sites/ar/$1 [L, QSA

#note, the above will also remove <sitename> from the final url, if you need that, add it to the destination url