Localized url_for let you get your scoped urls auto localized Example: All scoped urls on the page example.com/en

will look like:
  - http://example.com/en/contacts
  - http://example.com/en/about
  ...

Set locale from params:

Add it to ApplicationController

before_filter :set_locale
def set_locale
  I18n.locale = params[:locale] unless params[:locale].blank?
end

Config routes:

scope '(:locale)' do
  #get "/" => 'index#index', :as => 'index'
end