Ok, I turned to UIAccessibilityAnnouncementNotification for handling accessibility information, of course the issue for the utterance of the turn-by-turn directions for the other people stays. This is how I expressed the function:
func announcementFinished(notification:NSNotification){
activeAnnouncement=false
}
func read(text:String, onlyAccessible:Bool){
println("reading \(text)")
if UIAccessibilityIsVoiceOverRunning() && !activeAnnouncement{
UIAccessibilityPostNotification(UIAccessibilityAnnouncementNotification,
text);
activeAnnouncement=true
}
if (!onlyAccessible && !UIAccessibilityIsVoiceOverRunning()){
utterance=AVSpeechUtterance(string: text)
speechSynth.speakUtterance(utterance)
println("alla fine dell'if")
}
}