Language Not Available

I’m using the plugin Loco Translate to help me finish translating my site into Spanish (Mexico) to make my site multilingual for both English and Spanish (Mexico). Through the Loco Translate plugin I can select each plugin individually to see if there is a translation for the language I’m using, and if not, then I can add that language. Unfortunately when I attempt to add Spanish (Mexico) I’m told there isn’t a template available for this language. When I look in the documentation for Loco Translate it says if this occurs that either a template has not been provided for the plugin or it’s named something that Loco Translate can’t find. Can you tell me if there is a template for Spanish (Mexico), and if not can you provide one so I can translate this plugin to work for Spanish as well as English?