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Navigation SDK UX Framework comes in with a Text-To-Speech engine that's used to synthesize assistant's messages during conversation or active guidance. By default, a remote TTS engine is used to produce the most natural sounding voice, however, this can comes at a slight cost of data usage and latency.

You can configure UX Framework to use a local Text To Speech engine instead via the preferLocalTts flag:

val config = DashConfig.create(
applicationContext = applicationContext,
accessToken = getString(R.string.mapbox_access_token)
) {
preferLocalTts = true

You can also update the preference at any point in the runtime:

Dash.applyUpdate {
preferLocalTts = true

Make sure that the device has downloaded the offline language pack for the language that user selected.

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