How to turn on iOS Voice Control. Resolve “Unable To Turn On Voice Control. Failed to download necessary files.”

Regarding the issue: “Unable To Turn On Voice Control. Failed to download necessary files.” A lot of web sources referring “Automatic Update” / “Enable Background App Refresh” / “Low Power Mode”, etc. However tested all but still not work in the latest iOS 14.3.

Find out the “Automatic Update” setting is not relevant. After ensure the iPhone enabled “Background App refresh”, it needs 2 more conditions to enable Voice Control:

1. Siri Language must be English (United State).

Settings > Siri & Search > Language

2. iPhone Language must be English (US).

Settings > General > Language & Region > iPhone Language

Done! Now you can enable Voice Control.

Settings > Accessibility > Voice Control

After the Voice Control enabled, you can then revert back Siri and iPhone language to your preferred one. The Voice Control will still work in only English anyway.

Reference:

Voice Control isn’t available in all countries or regions. Voice Control uses the Siri speech recognition engine for U.S. English only.

https://support.apple.com/en-hk/HT210417