Which browser and OS are you using that switches the SVG file but not the SVG within HTML? It works for me in Chrome, Firefox, and Internet Explorer on Windows.
(As mentioned, the tooltips don't switch yet. That is something new for SVG 2.)
On your other points:
- You're right, using a dialog probably makes more sense then a sub-menu with all the language options. The list of languages could get very long. But you would open the dialog from the "View" menu.
- The issue of capitalization and language codes is a good point. Language tags are *supposed* to be case-insensitive, according to the document referenced from the SVG specs (http://www.ietf.org/rfc/bcp/bcp47.txt). But...
- In both Firefox and Chrome, the language code has to be all lowercase. IE accepted either.
- In Firefox and Internet Explorer, the country code works in either upper or lowercase. In Chrome, I couldn't get a language with country-code to work with any captitalization.
- Yes, you can use a single <switch> to switch between groups. When I said it was too complicated, I meant from the User Interface side, not from the SVG/XML side. But if you can come up with a good UI, great!
- Even if the default language does not have a systemLanguage attribute, or even if the user isn't switching languages at all, we should still ask for language, and use xml:lang to declare it, for accessibility reasons.
- But yes, it makes sense to use the first language they typed as the default, unless they set it to something else.