Thanks Rob and Mitch. Got back into it this morning and I'm scratching my head as well. Everything works as expected on Ubuntu and Windows Subsystem for Linux (i.e. Ubuntu). But no math in Windows.
Digging a little deeper (on Windows), the "math-representations-svg.xml" file has lots of math in it. The "math-representations-speech.xml" has content, but the elements appear to be empty (i.e., `<pi:math context="me" id="me-1"><div class="speech"/></pi:math>` and similar lines for each of the ids).
Fishy messages on the console: After PTX:DEBU calling mathjax to convert latex from ...mj-input-latex.html into raw representations as speech... I have "Unable to load local: base" and "Unable to load local: en" and then a bunch of "Something went wrong computing speech" (20 of them). Then PTX:DEBU packaging math as speech from ... into ...
On Ubuntu, I don't get the fishy messages, in particular I do NOT see the "unable to load local: base/en" messages.