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# init(installedSource:target:preferredStrategy:)

Creates a translation session to translate between a given source and target language already
installed on device.

```
convenience init(installedSource source: Locale.Language, target: Locale.Language?, preferredStrategy: TranslationSession.Strategy)
```

## Parameters

`preferredStrategy`

The translation approach to use.
[`highFidelity`](/documentation/Translation/TranslationSession/Strategy/highFidelity) uses Apple Intelligence
models when available on device, or falls back to [`lowLatency`](/documentation/Translation/TranslationSession/Strategy/lowLatency)
when those models aren’t available. The `lowLatency` strategy uses traditional
models for translation.

## Discussion

If one or both languages aren’t installed on the device, attempting to translate will
throw errors. To get the person’s permission to download languages that aren’t already
installed, translate using a [`TranslationSession`](/documentation/Translation/TranslationSession) provided by <doc://com.apple.documentation/documentation/SwiftUI/View/translationTask(_:action:)> or
<doc://com.apple.documentation/documentation/SwiftUI/View/translationTask(source:target:action:)> .

> Note: If you created `TranslationSession` using
> ``doc://com.apple.Translation/documentation/Translation/TranslationSession/init(installedSource:target:)``, you don’t need a
> `.translationTask()`; however, you will need a ``doc://com.apple.Translation/documentation/Translation/TranslationSession/sourceLanguage`` .

---

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