I am using AVSpeechSynthesizer to play text. I have an array of utterances to play.

    NSMutableArray *utterances = [[NSMutableArray alloc] init];
    for (NSString *text in textArray) {
        AVSpeechUtterance *welcome = [[AVSpeechUtterance alloc] initWithString:text];
        welcome.rate = 0.25;
        welcome.voice = voice;
        welcome.pitchMultiplier = 1.2;
        welcome.postUtteranceDelay = 0.25;
        [utterances addObject:welcome];
    }
    lastUtterance = [utterances lastObject];
    for (AVSpeechUtterance *utterance in utterances) {
        [speech speakUtterance:utterance];
    }

I have a cancel button to stop speaking. When I click the cancel button when the first utterance is spoken, the speech stops and it clears all the utterances in the queue. If I press the cancel button after the first utterance is spoken (i.e. second utterance), then stopping the speech does not flush the utterances queue. The code that I am using for this is:

  [speech stopSpeakingAtBoundary:AVSpeechBoundaryImmediate];

Can someone confirm if this is a bug in the API or am I using the API incorrectly? If it is a bug, is there any workaround to resolve this issue?