@atlaskit/editor-core - How to change Editor's language?

Hey. How do you get the Editor component translated? In the docs there’s an example:

import { IntlProvider } from 'react-intl-next';
// ...

return (
  <IntlProvider locale="en">
    <Editor />

However changing the locale doesn’t seem to do anything. The editor is always in English for some reason. I tried fr and de with the locale property and neither worked.

I have tried the IntlProvider from package react-intl-next, and also from react-intl (version 2.6 as recommended in the source repo and also the latest version - again no luck).

Another thing I tried is npm dedup as recommended in the readme of the repo, but no luck.

Am I missing something, or why is the Editor always in English? Lastly, assuming translations work, is it possible to supply translations for languages that are not in this list (e.g. French Canadian)?