Recently, I was in an Oslo bar visiting a friend. A Norwegian colleague of his was talking – in impressively fluent English – about the local nightlife, generously suggesting some bars we should visit while we were in town. As he mentioned one in particular, he paused for a second trying to find the word to describe it.

‘It’s quite…um…rock-y,’ he said.

He suddenly became uncharacteristically self-conscious, almost embarrassed, and laughed apologetically. His girlfriend – also Norwegian and with a similar mastery of English – joined in, mocking him for using (inventing) a word that he didn’t think existed.

‘I mean they play a lot of rock music there,’ he said.

For me, their reaction was striking. Of course, I understood exactly what he meant. He wasn’t referring to the state of the floors in the place (later I found out that they were a little bit sticky, but not uneven), nor to any film starring Sylvester Stallone. Although the Merriam-Webster dictionary doesn’t include ‘has a rock music vibe’ as a definition, the intended meaning of ‘rocky’ was entirely clear to me.

More importantly, he had only done what English speakers do all the time: That performance was a bit ‘bit-y’. That chicken was a bit ‘turkey-y’. Just last week I saw written on the side of my high-street Americano: ‘Our house espresso is always bold and intense with a chocolatey, caramel-y undertone.’

My friend’s colleague might not have applied a grammatical rule that features in Gwynne’s Grammar. But it’s still one that is a perfectly legitimate part of English. (Actually, it’s a highly productive example of derivational morphology, which I’ve blogged about before). On the spur of the moment, he had been creative with English, just like many English speakers would.

But I suspect the problem was this: as a Norwegian, speaking to an Englishman, he didn’t feel he had the right.

Creative play with words, sentences and phonemes – or language play as linguist David Crystal calls it – is ubiquitous. It might be most well known as something poets do, but language play is not something that is limited to literature and the arts. You only have to look at the tabloid headlines, watch an episode of Strictly Come Dancing, or even spend a night down the pub to find countless examples of everyday linguistic creativity. The use of metaphor and simile (‘she’s as quiet as a mouse’), hyperbole (‘that burger is enormous!’), intertextual references and rehashed clichés (‘keep calm and have a beer’), non-standard vocabulary (‘I’m going to take my automobile for a spin’), invented words (‘caramel-y’), and code-switching to other languages (‘mais oui, mais oui Rodney!’) are all part of what linguist Ronald Carter calls ‘the art of common talk’.

In conversation, people might use creative language with an element of performance – to show off, hold other people’s attention, or to make people laugh. Or, they might use creative language more subconsciously, to simply get as close as possible to the meaning they want to convey. This is what my friend’s colleague was doing when he used the word ‘rock-y’. It’s just that, as a non-native English speaker, he wasn’t sure he had the right.

So, when do you have the right to play with a language? Do you have to be a native speaker?

Maybe I have a lack of respect, but I’ve always taken great pleasure in butchering other people’s languages. In my early days of learning Mandarin, I was able to make my Chinese-Canadian partner giggle with joy by calling a ‘sock’ (‘wàzi’), a ‘foot-packet’ (‘jiǎobāo’). It was an entirely invented get-around, and I knew it wasn’t correct. But I also knew it would make me sound silly and childish, as well as gently poke fun at the wonderfully endless number of such compound nouns in Chinese – and that was entirely the point.

Some experts say that playing with language like this can even be beneficial. In his book Language Play, Language Learning, linguist Guy Cook points out the important role, often overlooked by teachers, that language play can have when it comes to learning foreign languages.

On one hand, language play can provide a fun way to draw attention to specific features of a language, in exactly the same way that nursery rhymes and nonsense words (‘Hickory, dickory, dock’) do for children learning their first language. I remember vividly the first time I heard a Swiss 4 year-old at a swimming pool say the charmingly-silly phrase ‘caca boudin’ (‘poo-poo sausage’). Thanks to him, although I’ve still never eaten one, I’ve never forgotten what a ‘boudin’ is.

On the other hand, language play can also give to students some sense of ownership of that language – as something they can use to whatever ends they need it for.

Picasso once said, ‘the chief enemy of creativity is good sense’. So, perhaps sensible people know better than to play with other people’s language. The rest of us language learners, however, should just carry on having fun.