A BCP 47 code identifying the voice’s language and locale.
- iOS 7.0+
- macOS 10.14+
- tvOS 9.0+
- watchOS 3.0+
The language of a voice controls the conversion of text to spoken phonemes, so the text spoken in an
AVSpeech should be written in the language matching that of the voice assigned to that utterance. The locale of a voice reflects regional variations in pronunciation or accent; for example, a voice with code
en-US speaks English text with a North American accent, and a voice with code
en-AU speaks English text with an Australian accent.