Text Speaker may read a punctuation character as a word when it is preceded by a dash.
You can change the pronunciation of the character combination by clicking Tools >> Pronunciation. Enter '-?' or whichever pronunciation you would like to change and replace the pronunciation with the silence character, a underscore '_'.
More information about adjusting pronunciation is available here:
https://www.deskshare.com/help/ts/AdjustingPronunciation.aspx