I am having the same problem as Will. I have expanded his code as follows: print("after let synthesizer") let utterance = AVSpeechUtterance(string: "Hello, testing speech synthesis on macOS.") print("after let utterance") if let voice = AVSpeechSynthesisVoice(identifier: "com.apple.voice.compact.en-GB.Daniel") { print("after let voice") utterance.voice = voice print("Using voice: \(voice.name), \(voice.language)") } else { print("Daniel voice not found on macOS.") } print("before synthesizer.speak") synthesizer.speak(utterance) print("after synthesizer.speak") The error message "Error reading languages in for local resources" appears at the if let voice… call. Also at synthesizer.speak(utterance) there are three of these: _-[AFPreferences languageCodeWithFallback:] No language code saved, but Assistant is enabled - returning: en-GB I am also getting: #FactoryInstall Unable to query results, error: 5 This is just MacOS (15.3ß), using Xcode 16.2 - I am not getting any of this for the identical code running in my iOS app.