[ttml2] Pull Request: Clarify derivation of special semantics of tts:directiion (#1024).

skynavga has just submitted a new pull request for https://github.com/w3c/ttml2:

== Clarify derivation of special semantics of tts:directiion (#1024). ==
Closes #1024.

See https://github.com/w3c/ttml2/pull/1147

Received on Friday, 30 August 2019 07:35:51 UTC