---
title: Localize the user interface
slug: cms-13/docs/localize-the-user-interface
docTags: 
createdAt: 2026-07-30T20:22:05.208Z
---

Localized UI text lets editors and visitors see the interface in their preferred language. The default localization service retrieves translated resource files from a predefined project folder.

The provider looks for XML string resource files in a `lang` folder under the content root. Add localizations or override system strings by placing files in that folder. Translations in the `lang` directory override system-defined resources.

By default, the UI language matches the editor's **Language Settings** > **Personal Language** selection. For more control, create a custom localization provider. Inherit from `LocalizationProvider` and register it as described in [Configure a custom localization provider](docId\:EAzswrSllDe-i8X7eFK0G).

## Register custom localization providers

Register custom localization providers with `LocalizationOptions`, `AddLocalizationProvider`, or `AddEmbeddedLocalization` on `IServiceCollection`. The following example registers an embedded localization provider for the assembly containing `Startup`:

```csharp
services.AddEmbeddedLocalization<Startup>();
```

After registering the provider, add XML language files such as `ContentTypeNames.xml` to that location. When using `EmbeddedXmlLocalizationProvider`, add them as embedded resources instead.

Language files accept any file name and support one or more languages per file. The following structure is required.

One language:

```xml
<?xml version="1.0" encoding="utf-8"?>
<languages>
  <language name="English" id="en">
  </language>
</languages>
```

Two languages:

```xml
<?xml version="1.0" encoding="utf-8"?>
<languages>
   <language name="English" id="en">
     ...
   </language>
   <language name="Swedish" id="sv">
      ...
   </language>
</languages>
```

## Add localized text

Localize text shown in the UI for content types by adding translations in a convention-based format. The following code example defines the `StandardPage` content type with attribute and property texts such as `MainContentArea`:

```csharp
[ContentType(Description = "Replace this text with an XML translation")]

public class StandardPage: PageData {
  [Display(
    GroupName = SystemTabNames.Content,
    Name = "Replace this text with an XML translation",
    Description = "Replace this text with an XML translation"
  )]
  public virtual ContentArea MainContentArea {
    get;
    set;
  }
}
```

For a `StandardPage` content type with these attributes and properties, the language file structure is as follows:

```xml
<language name="en">
  <contenttypes>
    <standardpage>
      <description>A description of the page type</description>
      <properties>
        <maincontentarea>
          <caption>Name text from XML</caption>
          <help>Description text from XML</help>
        </maincontentarea>
      </properties>
    </standardpage>
  </contenttypes>
</language>
```

### Reuse localization for properties between content types

Shared translations reduce duplication across content types that inherit common properties.

Add common translations to an inherited type such as `pagedata` or `icontentdata`.

The following content type defines a `Name` property that inherits from `PageData`:

```csharp
public class StandardPage: PageData {
    public virtual string Name {
      get;
      set;
    }
  }
```

The corresponding language file provides translations for the `pagedata` base type:

```xml
<language id="en" name="English">
  <contenttypes>
    <pagedata>
      <properties>
        <name>
          <caption>Name text from language file</caption>
        </name>
      </properties>
    </pagedata>
  </contenttypes>
</language>
```

Translations on interface types such as `icontentdata` apply to all implementing content types:

```xml
<language id="en" name="English">
  <contenttypes>
    <icontentdata>
      <properties>
        <disableindexing>
          <caption>Disable indexing</caption>
          <help>Prevents the page from being indexed by search engines</help>
        </disableindexing>
      </properties>
    </icontentdata>
  </contenttypes>
</language>
```

:::hint{type="info"}
**Note**
If base classes are not registered as content types, create a `UIDescriptor` for the base class to add translations.
:::

### Localize headers

Localized group headers let editors see tab labels in their preferred language. The following example localizes tabs used to group properties:

```csharp
public class StandardPage: PageData {
  [Display(GroupName = SystemTabNames.Content, )]
  public virtual ContentArea MainContentArea {
    get;
    set;
  }
}

public static class SystemTabNames {
  public
  const string Content = "Information";
}
```

The `GroupName` on `MainContentArea` refers to `SystemTabNames.Content`, which resolves to `Information`. Add a `<groups>` element with the group name as the child element:

```xml
<language name="en">
  <groups>
    <information>Group name from XML file</information>
  </groups>
</language>
```