The ruby markup module features the rp element to ease compatibility with browsers that don't support ruby markup directly. Non-ruby browsers render both the rp and rt element content as inline text. The rp element gives you a chance to include parentheses (or other character) around the ruby text so that the ruby text acts as an inline label. Content of each rp element is traditionally either a left or right parenthesis symbol. A complete rp element goes before and after each rt element. Browsers that support ruby text ignore the rp element content, and, thus, don't display the parentheses.

The language being used for the element's attribute values and content. A browser can use this information to assist in proper rendering of content with respect to details such as treatment of ligatures (when supported by a particular font or required by a written language), quotation marks, and hyphenation. Other applications and search engines might use this information to aid the selection of spell-checking dictionaries and the creation of indices.