Posting this here for visibility. Already opened a bug report but maybe this helps other developers. In our app we use AVSpeechSynthesizer to speak navigation directions. Our Dutch users notice that many of the utterances glitch, where it seems to speak a random '-' in-between the text. This is reproducible by simply speaking this text on a Dutch AVSpeechSynthesisVoice: "Over 300 meter houd rechts aan richting Breda." (which means "In 300 meters, keep right towards Breda."). It glitches on the word 'aan'. Reproducible only on-device, as the Xcode simulator doesn't seem to have this issue. Tested on iOS 14.4 and 14.6, where both have this issue. The issue is very obvious to hear. Texts that also have this issue: "Over 900 meter houd rechts aan en blijf op Muntweg." "Houd rechts aan." Reproducible on-device with the following code: // This is Dutch for "In 300 meters, keep right towards Breda." let reproducableSpeakText = "Over 300 meter houd rechts aan richting Breda." let speechUtterance = AVSpeechUtterance(string: reproducableSpeakText) // Configure a Dutch voice let dutchVoice = AVSpeechSynthesisVoice(language: "nl-NL") speechUtterance.voice = dutchVoice // Speak the text synthesizer.speak(speechUtterance)