This is the code that renders a ‘button’ for language switching in new Vector:
```
<nav id="p-lang-btn" class="mw-portlet mw-portlet-lang vector-menu vector-menu-dropdown" aria-labelledby="p-lang-btn-label" role="navigation">
<input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="mw-interlanguage-selector vector-menu-checkbox selector-open" aria-labelledby="p-lang-btn-label" data-uls-loaded="true" aria-expanded="false">
<h3 id="p-lang-btn-label" aria-label="Aller à un article dans une autre langue. Disponible en 322 langues." class=" vector-menu-heading mw-ui-button mw-ui-quiet mw-ui-progressive" aria-hidden="true">
```
It has multiple issues:
1. `aria-hidden="true"` on an element that is used throughout the interface as an accessible description (in `aria-labelledby`).
2. Long `aria-label` on the same element that does not seem to function correctly (not announced to screen reader software, at least as can be checked from Firefox’s Accessibility tools).
3. In combination, this seems nonsensical, as the whole menu should not be labelled by such a long label, and it seems really probable that `aria-label` / `aria-hidden` combo does nothing, or might cause problems with what gets read out in some screen readers.
Seems to be introduced by {T289523}. https://github.com/w3c/aria-practices/issues/1136 says that combining `aria-labelledby` with elements with `aria-hidden="true"` ‘seems like a bad pattern that should never be used’ (i. e. anti-pattern).
Old Vector also has a related issue, as well (`aria-label=""` should not be set by the skin on all portlets):
```
<h3 id="p-lang-label" aria-label="" class="vector-menu-heading">
<span class="vector-menu-heading-label">На других языках</span>
</h3>
```