Representational image.Creative Commons.

As entertaining or absolutely terrifying the experience of hearing someone talk in their sleep can be – especially so because the person doing it is blissfully unaware of it – experts claim that a sleep-talker is actually rude and the habit can be pretty offensive too.

Once known as somniloquy, sleep-talking is actually a disorder where people talk in their sleep without realizing they are doing it. And the things they blurt out could be anything – from absolutely nonsense to unexpressed emotions in the form of profound speeches.

Also read: Insomnia ruining your life?

But even though it's more common in little children and males, a research conducted by Dr Isabelle Arnulf shed light on the things people are more likely to blurt out during sleep-talking and as per the results, the responses are not that great and can often lead to an embarrassing situation.

As the reported, Dr Arnulf's research revealed that more often, the maximum amount of sleep-talking is filled with negative, vulgar words and profanity. Talk about awkwardness!

A total of 232 adults participated in the research and 129 out of them suffered from REM sleep behaviour disorder, 87 experienced sleepwalking or night terrors, one who had sleep apnea, and the rest had no sleep-related disorders.

[Representational Image] Get a good night's sleep by following these four steps.Getty Images/ PeopleImages

The participants were recorded sleeping over the course of a few nights and whatever they said – or did in their sleep was tracked. The most common word uttered was 'no', while 24 percent of sleep talk was containing negative content, and another 22 percent included 'nasty' language.

Not so surprisingly, almost 10 percent of all sleep-talking episodes involved swearing, with the f-bomb being dropped 800 times more often in participants' sleep than it was used when they were awake.

Interestingly enough, it was also revealed that while we might be increasingly profane in our sleep, the grammar skills remain intact.

Man unable to sleep while wife sleeps comfortably unaware.Getty Images/Frederic Cirou

"What we now know is that sleep talking is very similar to talking awake, in terms of correct grammar, with subordinate sentences, and silence for other[s] to answer, as in awake turn of speech," Dr Arnulf told MNT.

"The differences are qualitative: nocturnal language is negative, tense, more vulgar, and addressed to somebody, not to oneself. It suggests that the brain uses the same networks as awake and that sleep talking translates the concomitant dreaming activity, which is tense, too."

So it's clear – no matter how polite or courteous you are when awake, in your sleep your mouth is prone to run a little wild!