System-language dependant titles

[jnqnfe]

The <title> element allows for providing a 'short alternate text' for an element. Browsers will show this as a tooltip when hovering the cursor over the respective element, or, where used directly under an <svg> element, display it as a browser tab label or window title.

While the <title> element has a lang attribute, there seems to currently be no way of making <title> text depend upon system language, unlike <text> and <tspan>.

Use case example 1

I have an SVG diagram which includes some labels. To suit the diagram these labels have to be extremely short. For some of them it would be preferable to use a <title> to provide a slightly longer text variant which could be revealed upon hovering over the element, to aid with understanding. (Simply presenting longer labels in a smaller font would be far from ideal). This diagram though is multi-lingual, containing translations of all of the <text> labels via <switch> and systemLanguage. While translation works perfectly for the actual displayed labels, it seems to be impossible to translate such <title> tooltips (and the document title).

I tried using aria-label on the translated <text>/<tspan> elements as an alternative to using <title>, but neither Firefox nor Chrome display this as a tooltip.

I also tried using <switch> and <text>/<tspan> elements with systemLanguage under a <title> element in Firefox, but the tooltip just contained every translation, so it seems that use isn't supported (though I haven't double checked the spec).

Use case example 2

Such ability to translate <title> elements could be useful to the World Map SVG on wikipedia. This uses <title> elements such that when you hover over a country region a tooltip appears with the country name. As is though, only English names can be shown. If <title> translations were supported, it could display translated country names for different users. (Without having to create separate, translated copies of the file).

[Crissov]

SVG2 clarifies that user agents should choose the sibling <title> (and likewise <desc>) element that best fits the user’s linguistic preference by in-/respecting their lang (or generic xml:lang) attributes, by which they must differ.
That means, <switch> and systemLanguage are unnecessary and unavailable there; they are the correct tool for visible elements.

Note that the (xml:)lang attribute, unlike systemLanguage, only supports a single BCP47 language tag, not a list of codes. Since attribute may also never occur more than once per element, this necessitates repetitions where the value is coincidentally the same for multiple supported languages.
Legacy renderers should use the first sibling element; it is therefore good practice to either provide paralingual content like an emoji there with an empty language attribute, or to omit the attribute and use the inherited dominant document language therein.

In conclusion, there is no need to change the specification. Alas, I’m not sure whether browsers handle this correctly or whether they treat images labeled as conforming to SVG 1.x differently in this regard (which I highly doubt in general).

PS: Oh, Issue 67 puts this feature at risk for lack of implementations.

[pkra]

FYI I've filed w3c/svg-aam#40 to look into this at the ARIA WG's end.