[i18n-activity] tts:writingMode example is not helpful

aphillips has just created a new issue for 
https://github.com/w3c/i18n-activity:

== tts:writingMode example is not helpful ==
https://w3c.github.io/ttml2/spec/ttml2.html#style-attribute-writingMode

The illustration of the `rltb` writing mode uses unicodeBidi override 
and direction rtl to show some English text backwards. This isn't 
particularly helpful, since it isn't really an effect of writing mode 
and non-observant readers may not realize that the example has these 
features turned on in the example. The may attribute the RTL results 
to the writing mode. I would instead suggest showing the text strongly
 right aligned, possibly in conjunction with an Arabic or Hebrew 
translation.




Please view or discuss this issue at 
https://github.com/w3c/i18n-activity/issues/331 using your GitHub 
account