This was extracted from T254864: Wikispeech attempts, but fails, to play non-existing page

When an error occurs, we try to synthesise something which is too long, try to synthesise a non-existant page, Speechoid is unreachable etc., there is currently no audio feedback to the listener.

A mechanism for addressing this would be to set up some i18n messages which get synthesised on installation of the Extension. These could then be returned at the appropriate moments.

The difficulty will likely lie with injecting these messages into the database (they have no corresponding page), finding a good expiration method, we ideally want to re-generate them as seldom as possible to avoid them disappearing when there is an issue with Speechoid and we want to trigger a re-generation upon deployment of new i18n translation.