The Independent today has a fluff piece on "9 absurd things you're not allowed to do in [the UK] Parliament". Along with all the ones we have inherited - not speaking to one another directly, not calling people liars or hypocrites - there's also one which is outright offensive rather than merely absurd:
Speak in Welsh
The United Kingdom’s regions promote a number of languages: Most notably, Welsh has half a million speakers, Scots tens of thousands, and a similar number Irish.
Unfortunately for speakers of these languages, speeches in the House of Commons can only be made in English. Quotations in other languages are allowed, however.
Unlike in the European Parliament there are no live translation services available for members.
Pretty obviously, this is because the UK Parliament grew out of the English Parliament, which viewed the other constituent nations of the UK as subject peoples to be lorded over, rather than partners. But the UK isn't supposed to be like that now - instead its supposed to be a partnership, and is evolving towards a loose federation. In the modern UK, refusing to recognise the languages of the UK's constituent nations is a denial of that nationhood - and therefore of that partnership. Which isn't the way to go if you want those nations to stay together.