I don't want the user to have to change the voice. I think I have found how it is done. I have to embed the command to change the voice <voice required="name = Crystal16"> at the start of my text which is copied to the clipboard. This is relatively easy for me to do.
Thanks for your help
What I did for similar tasks and the German language was to go to the Pronunciation editor and define things like
<voice required="name = Crystal16">
<voice required="name = premium_male_german_voice">
(DE=Deutschland / Germany)
So now I can enter my voice changes quickly and in a way that is easy for me to remember.
A male English voice? EN_M
A female Spanish voice? SP_F
and so on....
And if I decide to change from male to female or vice versa, a simple search and replace does the trick. Another plus is that the voice changes no longer clutter up the screen or take up so much screen space.