Rails 4 i18n, how to translate routes where subdomain is used for the locale

I am using subdomains to determine the locale in a Rails 4 website. I have this working with a locale switcher exactly the way I want it but now I need to translate the routes and I'm not sure about the best way to proceed.

I have looked the https://github.com/kwi/i18n_routing i18n routing gem but this doesn't work with subdomains, it seems to change the path by adding /locale which is not what I need.

Other gems seem to be out of date with Rails 4.

Edit

Basically I want to be able to use the same view helpers but have the urls change to use whatever language is reflected by the selected sub-domain. this is just about route translation.

I have language specific templates which work and I can produce language spevific navigation templates but I would really like to not have to worry about changing erb path and url erb tags

End edit

A sample from routes.rb

scope module: 'countries', shallow: true do

  get 'south_american', to: 'south_america#index', as: :south_america
  scope module: 'south_america' do
    get 'south-america-weather', to: 'weather#index', as: :south_america_weather
    get 'south-america-gps-maps', to: 'gps#index', as: :south_america_gps
    get 'south-america-accommodation', to: 'hotels#index', as: :south_america_hotels
    get 'south-america-vacations', to: 'vacations#index', as: :south_america_vacations
    get 'south-america-facts', to: 'facts#index', as: :south_america_facts
  end

Using south_america_hotels_path as an example will generate a url for

south-america-accommodation

which is great but how would I translate this so that when I am on the Spanish subdomain south_america_hotels_path will generate the following url

hoteles-en-sudamerica

UPDATE

Also how would this work for a url rather than just a path so that south_america_hotels_url will generate

en.some_site/south-america-accommodation

and when on the spanish subdomain I would get

es.some_site/hoteles-en-sudamerica

and so on for the different locales involved.

I am happy to use yml files for the translations for the urls or to define the additional routes in the routes.rb file, either is an option but I would prefer to define the url's in the routes.rb but I am unable to find a way to provide language specific urls for the same :as path/url option based on subdomain.

Update and further clarification in response to previous replies.

Changing the url's is not an option, they need to match existing url's. I just need to know how to translate them from a view helper point of view without having to change the view helpers.