I've tested and found that SpeechTranscriber.isAvailable returns false on these devices. iPhone 11 iPhone 11 Pro iPhone 11 Pro Max iPhone SE 2nd Generation Here is my assumption: iOS 26 models with an 8-core Neural Engine do not support SpeechTranscriber iOS 26 models with a 16-core Neural Engine support SpeechTranscriber You can check your model's neural engine core from the link below. https://www.apple.com/iphone/compare/ This assumption perfectly aligns with the test result I've done so far. If it's true, Apple should clearly state this requirement in their documentation.