<!--
{
  "availability" : [
    "iOS: 7.0.0 -",
    "iPadOS: 7.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.9.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "AVFoundation",
  "identifier" : "/documentation/AVFoundation/AVAssetWriterInput/extendedLanguageTag",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "AVFoundation"
    ],
    "preciseIdentifier" : "c:objc(cs)AVAssetWriterInput(py)extendedLanguageTag"
  },
  "title" : "extendedLanguageTag"
}
-->

# extendedLanguageTag

The extended language for the input’s track.

```
var extendedLanguageTag: String? { get set }
```

## Discussion

Extended language tags are normally set only when an ISO 639-2/T language code alone is ambiguous. For example, you may use an extended language tag to distinguish media by the regional dialect in use or the writing system employed.

Specify the value as an RFC 4646 language tag, or `nil` to prevent the writer from writing an extended language tag.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)