---
title: Add languages
slug: cms-11/dev-docs/adding-languages
docTags: 
createdAt: 2026-07-22T19:45:19.643Z
---

This is useful when you want to add less commonly used language and local combinations to an Optimizely Content Management System (CMS) installation.

CMS takes the list of languages you can enable for a site from the languages installed on the host operating system. Available languages can present a problem because they vary between different machines.

To add a language, install it on your operating system through the `CultureAndRegionInfoBuilder` class in `System.Globalization`; you can create or copy a language (although you will have to run the code in the context of an Administrator account for it to work).

## Add a language to the list of available languages

The following code sample shows how to use `CultureAndRegionInfoBuilder` to create and register a language based on an existing language, in this case, creating Hong Kong English (**en-HK**) from UK English (**en-GB**). You need a reference to `sysglobl.dll` in your project for this to compile.

:::hint{type="info"}
**Note**
Custom cultures such as ”sv-gb” and "en-fr" are not supported for solutions running in Optimizely Digital Experience Platform (DXP). See Optimizely DXP - Multisite Development.
:::

```csharp
public static void CreateCulture() {
  //* Get the base culture and region information
  CultureInfo cultureInfo = new CultureInfo("en-GB");
  RegionInfo regionInfo = new RegionInfo(cultureInfo.Name);

  //* Create the a locale for en-HK
  CultureAndRegionInfoBuilder cultureAndRegionInfoBuilder = new CultureAndRegionInfoBuilder("en-HK", CultureAndRegionModifiers.None);

  //* Load the base culture and region information
  cultureAndRegionInfoBuilder.LoadDataFromCultureInfo(cultureInfo);
  cultureAndRegionInfoBuilder.LoadDataFromRegionInfo(regionInfo);

  //* Set the culture name
  cultureAndRegionInfoBuilder.CultureEnglishName = "English (Hong Kong)";
  cultureAndRegionInfoBuilder.CultureNativeName = "English (Hong Kong)";

  //* Register with your operating system
  cultureAndRegionInfoBuilder.Register();

}
```

1. Run the code.
2. Start Optimizely CMS.
3. Go to the admin view.
4. Select **Config tab** > **Manage Website Languages**.
5. Click **Add Language**. Your local combination is ready to use.