Misuse of <sup> to convey ruby annotations

“Ruby” are short runs of text alongside the base text, typically used in East Asian documents to indicate pronunciation or to provide a short annotation.

In the following Japanese text, み, か, だお are ruby annotations that indicate to the reader how the kanji characters 見, 掛, 倒, respectively, should be pronounced.

In this example, a well-meaning author has used <sup> (i.e., superscript) elements and custom CSS to visually convey ruby annotations. This is a failure because assistive technologies cannot programmatically determine the structured ruby annotations that are visually presented.