I faced the problem that negative (temperature) values (as occurring these days outside…) are converted into speech without the “minus”, e.g. “-6°C” is spoken as “sechs”.
This problem occurs with MaryTTS as well as picoTTS. (Strangely enough, when using Spanish or Italian in picoTTS, the “minus” was spoken).
Finally I detected by chance that the “minus” is omitted when the preceeding word in the sentence (see below) has no “blank” (pause) before the variable with the number.
say ( “Die Aussentemperatur beträgt” (AussenTemperature.state as Number).intValue + " Grad") }
// the “minus” is not spoken
say ( “Die Aussentemperatur beträgt_” (AussenTemperature.state as Number).intValue + " Grad") }
// the “minus” is spoken