Why Not Ruby Tags?

[Pipian]

This is sort of an off-the-cuff suggestion, but with HTML5 being nominally based off HTML4/XHTML1 with additional useful semantic tags, I'm a little surprised that, at the very least, the ruby tags from XHTML1.1 have not been included. The semantics they imply, namely annotations (either above or below the text) seem to not be very well marked in existing HTML4, other than with a catch-all span element with a certain class, or permuting the semantics of one of the list elements.

Lastly, its usefulness in listing inline annotations (particularly having to do with its use in distinguishing semantic content from phonetic content in Asian contexts) is not handled at all in existing HTML4. While I think it would have limited use in most contexts, educational or academic contexts could benefit from the annotational semantics added through the ruby elements, not unlike the abbr element, though with more flexibility in indicating semantics of a passage with multiple levels of annotation possible, as well as multiple divisions of wording within a single semantic unit.

[zcorpan]

IIRC, Hixie has said that Ruby will be included in due course. It hasn't been included yet because no-one has figured out how error handling is supposed to work yet.