Change URL Pages for Different Languages in Magento 1.9

First of all you need to check you website structure, from your comments it's like you already have 2 store view in a single website.

So if you want to be Spanish as your default language you need to go to system > configuration > general - locate option the you need to change your "current configuration scope" to "store view" and in click use default false from the combo of location options and search for Spanish - Spain ( you mast have already installed language package of Spanish from Spain to see Spanish).

Well, I hope this can help, let's know if you need feature help.

Best, ALe.

Here is the solution

https://github.com/jreinke/magento-hide-default-store-code

Remove this format: ?___store=english for english and ?___store=arabic

In the design file find the languages.phtml

/app/design/frontend/default/template/page/switch/languages.phtml

In the line 41

echo $_lang->getCurrentUrl()

Add 'false' as parameter

echo $_lang->getCurrentUrl(false)

Actual Url:

http:example.com?___store=english for english and ?___store=arabic

After added the false parameter in $_lang->getCurrentUrl(false) method. Url will be generated like the below

http:example.com?___store=english