I know that this has been requested in the past (quite a few years ago already). Word and Pages both have the ability to add phonetic text to CJK characters. It's a badly needed feature for a WP that is known for its functionality in handling multiple languages. Word works nicely for aligning text above characters; Pages will struggle depending on the font used.
Redlers, any hope of expecting this in the future?
Ruby and vertical text for CJK
Moderators: Eyal Redler, redlers, Ori Redler
Re: Ruby and vertical text for CJK
I second this, along with the perennial request for support for Indic scripts.