“Last time policeman also wear shorts,” a man told me in Singapore a few weeks ago. I wondered if this was a commentary on local fashion, or maybe an oblique political statement. In Singapore, freedom of speech is far from absolute. But no, all he meant was “That’s nothing new.”

The remorseless sprawl of English has given much of the world a lingua franca: ours. In the 21st century, no matter where you are, you can generally find a regional newspaper in English, and watch CNN or BBC World. The impact on some minority languages has been severe. But lately I’ve come to realise that the spread of English can also have a very different effect: it has helped to create a space where new forms of language can emerge.

Singlish — otherwise known as Singapore Colloquial English — is one of them. It grows out of a raw, rough, vibrant mix of English, Malay, Tamil and the languages of southern China, Hokkien in particular. I spent an evening in the Singapore Cricket Club with a Tamil lawyer who announced, after his third whisky: “Profanities come to me most easily in Hokkien.”

He meant phrases like “lan tui”, which is, according to the informal and invaluable Coxford Singlish Dictionary, the local equivalent of “Up yours!” The literal meaning is “penis split”. You just drop the phrase into a gobbet of conversation, as in “You want me to make dinner for you again? Lan tui!” My favourite Singlish phrase is a long chunk of language, lifted straight from Hokkien, that women might prefer to avoid: “Giah lum pah chut lai tom to’teng.” Use this only if you’re a man and are feeling seriously upset or embarrassed. It means “to take one’s testicles out and bang them on the table”.

Lots of Singapore expressions, of course, are not obscene, and have nothing to do with Hokkien or any other Chinese idiom. The local equivalent of “je ne sais quoi” is “very what one” — thus the delightful sentence “She very what one, you know?” Try saying that in the pub; maybe the phrase will take off in the UK.

Just like a Texan drawl or a self-conscious use of Estuary English, Singlish is a signifier of identity. Not only does it make a statement; it is a statement. It’s also a work in progress. There are no grammatical rules that a Singlish speaker is obliged to follow. The language is created afresh on the blistering streets every day.

But language creation can happen anywhere. The fragmentation of society means that all of us belong to groups, subgroups, even sub-subgroups of one kind or another. As a result, all of us make use of a specialised vocabulary that can bemuse other people.

Last time policeman also wear shorts, you say? Maybe so. Blacksmiths and shepherds had a big working vocabulary which is largely forgotten now. I own a copy of the Dictionary of Newfoundland English, a 770-page tome full of arcane fishing terms like corfish, trouncer, yarking and slob hauler. Now that the industry is all but gone (factory ships destroyed the resource), such words are unlikely to endure.

In the past, though, the words of a Newfoundland fisherman or a Cumberland shepherd remained private. Few people outside their region ever heard them speak. Today, thanks in part to the internet, we are lit up by words. Even the Coxford Singlish Dictionary can be found online, at www.talkingcock.com.

The specialised languages of music are a potent source of new terms, ones that often baffle. “Brooks is a maximalist to the core,” a music critic wrote last year, “suggesting an alternate path bleep could have taken, incorporating Hyper-On Experiences’ spastic bricolage and deep house’s sensurround production”. Say what?

Song lyrics can be equally puzzling — except to those in the loop. On Dutty Rock, the 2002 CD by the Jamaican dancehall singer Sean Paul, a single verse contains a mixture of apparent nonsense (“chippy lippy lippy loo”), fairly standard English (“let’s go together correspond woman”), and something that may look like nonsense but isn’t (“dutty cup we deh a haffi sing”).

Paul’s hit song Get Busy includes the line “Me want fi see you get live ’pon the riddim weh me ride.” And how will this happen? As the next line explains, “Me lyrics a provide electricity.”

You might respond that Paul is guilty of degrading the English language. But what’s more important is that he has the confidence to deploy and adapt Jamaican dialect for an international audience — and get rich in the process.