As far as I know, none of these are offical ISO language codes so you won't be able to use them

Fingers crossed for you, sounds like you are part way there though

Hi Huw,

Unfortunately Locales installed using this program dont show up in windows - so it was a false hope. (English - Malaysia) is in there.

We finally got a solution using Umbraco 10 - Kindly provided by Alex Razvalinov at the agency UKAD .

this involved intercepting the dropdown in the languages dropdown of the backoffice

This is the interceptor code which you add in a folder within App_plugins folder using a package.manifest

angular.module('umbraco.services').config([
    '$httpProvider',
    function ($httpProvider) {
        $httpProvider.interceptors.push([
            '$q', '$injector', 'notificationsService', function ($q, $injector, notificationsService) {
                return {
                    'request': function (request) {
                        // Redirect any requests to built in property editor and instead redirect to our own
                        if (request.url.indexOf("/umbraco/backoffice/umbracoapi/language/GetAllCultures") === 0) {
                            request.url = "/umbraco/api/LanguagesHelper/Languages";
                        }
                        return request || $q.when(request);
                    }
                };
            }
        ]);
    }
]);

using Microsoft.AspNetCore.Mvc;
using System.Globalization;
using Umbraco.Cms.Web.BackOffice.Controllers;
using Umbraco.Cms.Web.Common.Controllers;
namespace YOURNAMESPACEHERE.Web.Controllers {
    public class LanguagesHelperController : UmbracoApiController {
        public LanguagesHelperController() {}
        [HttpGet]
        public IActionResult Languages() {
            var cultures = CultureInfo.GetCultures(CultureTypes.AllCultures).ToList();
            var customCultures = new List<CultureInfo>()
            {
                new CultureInfo("en-lb"), 
                new CultureInfo("en-jp"),
                new CultureInfo("no-no"),
                new CultureInfo("en-et"),
                new CultureInfo("en-et"),
                new CultureInfo("en-hu"),
                new CultureInfo("en-th"),
                new CultureInfo("en-do"),
                new CultureInfo("es-do"),
                new CultureInfo("zh-my"),
                new CultureInfo("zh-cn"),
                new CultureInfo("zh-hk"),
                new CultureInfo("zh-tw")
            };
            cultures.AddRange(customCultures);
            var combinedCultures = cultures.DistinctBy(x => x.Name).OrderBy(x => x.EnglishName).ToDictionary(x => x.Name, x => x.EnglishName);
            return Ok(combinedCultures);
        }
    }
}

Whats the trick to pasting c# code into this forum? I have been trying to paste this code for 10 minutes and it still looks sh*d!

Thanks Huw

Its important to note that some combinations of language-country will be invalid and will throw an error.

This was our package.manifest for this, you might/will probably have to change the paths etc.

{
    "name": "Languages Interceptor",
    "version": "1.0.0",
  "javascript": [ "~/App_Plugins/LanguageHelper/languagesInterceptor.js" ]
}

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