I'm trying to add Greenlandic to an existing website. On my local development machine, the language is available as "kalaallisut (Kalaallit Nunaat)  kl-GL", but when I try enable the same language our on staging server, the language is not available in the list shown on the "Manage Website Languages" screen.

I've also noticed "kalaallisut kl" was availble on my local machine on another site, but not for the site I'm working on now.

What determines which languages are available and how do I enable Greenlandic on our staging server?