[1] Bug 326375 - Camino only, SVG: systemlanguage is not implemented (switch?) https://bugzilla.mozilla.org/show_bug.cgi?id=326375
[4] Document Structure — SVG 2 (, ) https://svgwg.org/svg2-draft/struct.html#SystemLanguageAttribute
[5] Synchronized Multimedia Integration Language (, ) https://www.w3.org/TR/1998/REC-smil-19980615/#test