What do the British call a television?
The British native languages – especially Celtic.
Among the British languages we have Teledu in Welsh and in Breton the endearing term Skinwel, although despite Britannic it isn’t spoken in the UK. I couldn’t find the Cornish term, but another commentator has it. Nor Manx, although presumably they have them. Irish Gaelic is Teilifís, Scots Gaelic is telebhisean, and the Lowland Scots article in Wikipedia says “Televeesion” although I am not such if that’s official usage, and as far as the Old English word they use, I think we can be pretty sure that’s an anachronism. As Abe Lincoln famously said, “don’t believe everything you read on the internet”. In that vein the Pictish term for TV is VOD as this enables you to “pict” what you like, when you like.

British dialects of English
If you are thinking about British versions of English and the regional or slang terms, I can’t think of any regionalisms. “Telly” is an informal way of talking about television as a service or the actual set, and further slang words for the set exist such as “the box” or “the gogglebox”. The term “tube”, hwever, was not widely used in British English slang and is more of an Americanism which I am not sure many of us would have understood prior to YouTube popularising it.
Community languages
Immigrant communities in the UK exist and the Poles have telewizja, while the words in Indian languages are mainly recognisable as something sounding like the original Standard English word (ie Greek roots put together in such a way that Oedipus could have forgiven his father) but written in their own alphabets and there are quite a few of them.
You can probably get by in the British Isles just using “television”, this weird partly Greek partly Latin word which was put together in the UK by an inventor whose command of physics was clearly many metres per second better than his command of philology.
Is this the “Talking with imbeciles”, series, or what?
Not really. This is part of a new series where I bring over, updating and re-writing where needed, the best of my answers to questions on Quora. I made a few of these in earlier years in chronological order. For now, I am moving them in the order of the number of upvotes received. These being the ones I would most regret losing. That is what they threatened me with over there for not being a Neo-Marxist. Over the course of 2022, on even numbered dates in the months, I plan to bring home to http://www.huliganov.tv as many of the best of these as I can manage. Where relevant, also to http://www.quoracy.com . I’ll be improving them, updating them, adding images. I warmly invite discussion below in each case. Enjoy!”
Original Posting Date:
Question as answered: What do the British call a television?
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Maybe the “box” itself will become defunct when more people come to realise it broadcasts a combination of mindless drivel, propaganda, advertising, ego-centric “personalities”, blatant lies and desperately poor comedy which is a tragedy in itself. So that leaves the better option of looking at a blank screen or better still, going for a nice hot brew. This, at least enables one to think one’s own thoughts without undue manipulation. The opening lines of the Francis Cabrel song “Carte Postale” come to mind…”Allumés les postes de télévision
Verrouillées les portes des conversations” but, I suppose, mobile phones have taken over that function now.
Indeed. When the mobile phone in its modern form appeared, with it came all childhood dreams of having like a little telly with you everywhere you went and be able to watch whatever or listen. The only things I wanted as a kid that I don’t have in the mobile phone are a robot tiger to go around with me, a model killer whale you can get inside of and travel the seas, and a flying bed. I also wanted like a huge sythesiser organ that you can make music on, but a computer, and therefore a mobile phone, can do that too, only I haven’t mastered the skills for that.
However, it is not great not to have much left to wish for. The “crook in the lot”, as puritan Thomas Boston put it in his eponymous book, is needful so that we keep a proper perspective.