This is a common question for English speakers: which is correct.? As usual, the real answer is complex, and possibly even interesting. But first, the simple answer: we use hung to refer to hanging an inaminate object, and hanged to refer to hanging a person. And if you find that hard to remember, don’t worry!: there are plenty of people out there who will be more than happy to correct you if you get it wrong! But I wonder: would they be able to explain to you why you’re wrong?
Well, let’s first see if we can figure out why we these two different forms for the same verb. Because it is unusual. It’s not like you can do that with any verb: you couldn’t choose to say either sang or singed, for example. I think part of the reason for this situation is that Proto-Germanic featured two very similar verbs, both of which developed into the modern-day verb to hang. First there’s the verb hanhan (very cute, isn’t it?), which is a transitive verb. This means that it must be followed by an object, e.g. I’m going to hang the painting. But there’s also the verb hangen, which is intransitive (it doesn’t take an object). As in the following sentence: The poster is hanging down. I think it’s no coincidence that to hang is both transitive and intransitive (as evident in the above example sentences), borrowing elements from both of these old verbs. And I think that its dual ancestry is also probably why it developed in two ways.
In the form hang/hung/hung, it’s an irregular verb, and in the form hang/hanged/hanged, it’s a regular verb (i.e. you form the past-simple and past-participle forms by adding -ed). 97% of English verbs are regular, but curiously enough, the ten most-commonly used verbs are all irregular (e.g. be/is/are/was/were/been, do/did/done, have/had/had). The reason for this is that most of them date to the time of the earliest forms of English, before the modern form of regular verbs developed. This longevity, coupled with the fact that they’re all fundamental verbs we use all the time, mean that they’ve never changed their form significantly.
And this is probably why hung is more common than hanged. We instinctively know that it’s an ancient, venerable verb form, and we’re therefore more attracted to it (and yes, the shift from hang to hung is an example of the ablaut pattern). The regular form, on the other hand, no matter how prevalent it is now, is still newer and perhaps viewed with a little mistrust. It’s too clean and simple, and lacks those blunt, earthy vowel sounds. In that case though, why did hanged survive at all?
I think it survived as a legal term because of the need for clarity in legal language. Hung sounds like too many other monosyllabic words, and might be confused for something else. Can you imagine the awkwardness of a defendant asking Sorry? I’m to be rung in the morning? Oh, that’s nice. Who’s going to be ringing me? My wife and kids? Boring old hanged on other hand, is pretty clear. I also think there’s something that tells us that it’s not right that we use the same verb to refer to hanging an inaminate object and to hanging a person. It seems like an affront to human dignity somehow to lump us together with such mundane objects as paintings and coats. Instead, I believe, we use hanged because its regularity sounds more formal and more respectful. Hung might come more naturally to us, but that also makes it sounds common, mundane. Though how much a person waiting to be hanged would feel their dignity satisfied because the judge said hanged is debatable to say the least: I’ve some good news and some bad news. The bad news is that you’re going to be hanged tomorrow. But the good news is, at least you won’t be hung!
And while I find it interesting to ponder why the word has these different forms (and I assume that if you’ve made it this far, you do too), I’d like to return to an idea from the opening paragraph: people correcting others for using the wrong form. Usually no-one would do this to a stranger, as this would be quite rude, though people are of course more likely to correct strangers’ errors online where they’re protected from a punch in the face. I think most of us understandably get annoyed at people who correct our errors, but I’ve always been curious as to why people want to correct other people’s mistakes. For me, the only legitimate reason could be if someone is saying something that could be misunderstood in a serious context. Or maybe if the mistake sounds really embarrassing. But hung/hanged? Is it ever really necessary that we use the correct form? If Homer Simpson said I’ll see that Quimby kid hung for this!, I think we’d all still understand him. Correcting him wouldn’t serve to improve communication in any significant way. Therefore the only reason I can think for correcting someone for saying hung instead of hanged would be to show off your superior knowledge.
And I don’t think we should stand for that. That’s why if someone corrects you on something like this, you should demand that they explain why what you said is wrong. And don’t take It’s just wrong for an answer. They need to explain why, I seen it, for example is wrong in some significant linguistic sense. Does it impede communication? Is it mistakeable for another phrase with a different meaning? And if they can’t think of a good reason, then maybe they’ll realise that language is about communication between people, and not strict accuracy. And that if you’re not following currently-accepted grammatical conventions, but still getting your message across, well, maybe that’s not so bad. I won’t go on any more on this topic, as I’ve covered it before (pedants really bug me). I will say though, that if someone corrects you for using hung instead of hanged, but then goes on to bore you with the history of hanhan and hangen, and Indo-European ablaut, maybe then you can then defer to their superior nerdiness and let them win that one!