Nathan,
Thanks very much for the response and overview that gives a very good explanation of why I’m experiencing problems. I note too your idea about AWS but will pursue something different for a while. There are several firms that offer online text to MP3 through a web UI. I’m going to reach out to a couple and see if I can entice them to extend the service to an API. That would give me the ability to send a text string and get an MP3 back - which is what I wanted from Polly. I’ll provide an update when I get a sense as the whether this might be a potential approach. From a business perspective I would think that it would be a relatively small investment in development effort for them to see an increase in the usability of their existing service.