I had to do similar recently. Basically, you have to create a console application and run it once to create the culture on each machine (e.g., staging, production):

// Namespaces.
using System;
using System.Globalization;
using System.Linq;

/// <summary>
/// Console application that ensures the necessary cultures exist on the system.
/// </summary>
/// <remarks>
/// This console application was necessary because some systems don't contain the necessary
/// cultures, and this logic couldn't reside within the website as the creation of new
/// cultures requires administrative privileges.
/// </remarks>
class Program
{

    #region Main

    /// <summary>
    /// Main entry point for the console application.
    /// </summary>
    static void Main(string[] args)
    {
        EnsureCulturesExist();
    }

    #endregion

    #region Private Methods

    /// <summary>
    /// Ensures all the necessary cultures exist (e.g., "en-AT" doesn't exist on some computers).
    /// </summary>
    /// <remarks>
    /// Some of this code comes from https://msdn.microsoft.com/en-us/library/system.globalization.cultureandregioninfobuilder.aspx
    /// and http://stackoverflow.com/a/16476935/2052963.
    /// </remarks>
    private static void EnsureCulturesExist()
    {

        // Variables.
        var allCultures = CultureInfo.GetCultures(CultureTypes.AllCultures);
        var ignoreCase = StringComparison.InvariantCultureIgnoreCase;

        // Reusable cultures/regions.
        var english = CultureInfo.CreateSpecificCulture("en-US");
        var austria = new RegionInfo("AT");
        var germany = new RegionInfo("DE");
        var sweden = new RegionInfo("SE");
        var switzerland = new RegionInfo("CH");

        // Register English (Austria) / "en-AT".
        var englishAustriaExists = allCultures.Any(x => "en-AT".Equals(x.Name, ignoreCase));
        if (!englishAustriaExists)
        {
            var englishAustria = new CultureAndRegionInfoBuilder("en-AT", CultureAndRegionModifiers.None);
            englishAustria.LoadDataFromCultureInfo(english);
            englishAustria.LoadDataFromRegionInfo(austria);
            englishAustria.CultureEnglishName = "English (Austria)";
            englishAustria.CultureNativeName = "English (Austria)";
            TryRegisterCulture(englishAustria);
        }

        // Register English (Germany) / "en-DE".
        var englishGermanyExists = allCultures.Any(x => "en-DE".Equals(x.Name, ignoreCase));
        if (!englishGermanyExists)
        {
            var englishGermany = new CultureAndRegionInfoBuilder("en-DE", CultureAndRegionModifiers.None);
            englishGermany.LoadDataFromCultureInfo(english);
            englishGermany.LoadDataFromRegionInfo(germany);
            englishGermany.CultureEnglishName = "English (Germany)";
            englishGermany.CultureNativeName = "English (Germany)";
            TryRegisterCulture(englishGermany);
        }

        // Register English (Sweden) / "en-SE".
        var englishSwedenExists = allCultures.Any(x => "en-SE".Equals(x.Name, ignoreCase));
        if (!englishSwedenExists)
        {
            var englishSweden = new CultureAndRegionInfoBuilder("en-SE", CultureAndRegionModifiers.None);
            englishSweden.LoadDataFromCultureInfo(english);
            englishSweden.LoadDataFromRegionInfo(sweden);
            englishSweden.CultureEnglishName = "English (Sweden)";
            englishSweden.CultureNativeName = "English (Sweden)";
            TryRegisterCulture(englishSweden);
        }

        // Register English (Switzerland) / "en-CH".
        var englishSwitzerlandExists = allCultures.Any(x => "en-CH".Equals(x.Name, ignoreCase));
        if (!englishSwitzerlandExists)
        {
            var englishSwitzerland = new CultureAndRegionInfoBuilder("en-CH", CultureAndRegionModifiers.None);
            englishSwitzerland.LoadDataFromCultureInfo(english);
            englishSwitzerland.LoadDataFromRegionInfo(switzerland);
            englishSwitzerland.CultureEnglishName = "English (Switzerland)";
            englishSwitzerland.CultureNativeName = "English (Switzerland)";
            TryRegisterCulture(englishSwitzerland);
        }

    }

    /// <summary>
    /// Attempts to register the specified culture, swallowing any errors that may occur.
    /// </summary>
    /// <param name="culture">
    /// The culture to register.
    /// </param>
    private static void TryRegisterCulture(CultureAndRegionInfoBuilder culture)
    {
        try
        {
            culture.Register();
        }
        catch
        {
        }
    }

    #endregion

}

That basically copies existing cultures to create new ones. You can modify it slightly for the culture(s) you want to create.

Hey, I forgot to respond. This looks awesome. I was actually not able to do this because of certain restrictions in our environment, so I wrote some cheesy code to handle "if culture X is required, act like it's culture Y with these special changes."

But good call for the insight. I see now that Umbraco just uses cultures in the system already and not some list specific to Umbraco. Thanks for the knowledge!

Jeremy

Are you aware of that Norway and Sweden are two different countries? And they have to different languages? se-SE and nb-NO.

Using Norwegian language in a Swedish site may give you letters not used in the Swedish language. And vice-versa.

I guess you should use se-SE or just SE for your Swedish site. For your Norwegian site you should use nb-NO (Bokmål) since Nynorsk is a dialect.

// Sigurd from Norway.

It seems there exists a culture code se-NO .. and both se-SE and sv-SE.

From what I have read the cultureInfo and country codes are OS dependant. http://azuliadesigns.com/list-net-culture-country-codes/

https://msdn.microsoft.com/en-us/library/cc233982.aspx

The culture in Umbraco backoffice are added to the dropdown here: https://github.com/umbraco/Umbraco-CMS/blob/5397f2c53acbdeb0805e1fe39fda938f571d295a/src/Umbraco.Web/umbraco.presentation/umbraco/create/language.ascx.cs#L23-L35

Maybe this explains it further http://stackoverflow.com/a/22808123

CultureInfo.GetCultures is not designed to be a complete and definitive list of all the cultures in the world. It's only designed to get you the cultures that can be found on the computer.

/Bjarne

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