I was born within the sound of Bow Bells, so I'm a Cockney. I grew up speaking like a Cockney. Cockney isn't just rhyming slang (and most of the rhyming slang dictionaries I've seen are 80% invented, and would never be used by real Cockneys).
Cockney is only partly the famous rhyming slang. It's also dropped 'H's at the beginning of words and syllables (be-ave yerself), 'th' replaced by 'f', dropped 'G's at the ends (listen ere, darlin), and glottal stops in the middle replacing 'T's and other unimportant consonants (a drin' a wa'er). I really can't describle the glottal stop, it's a consonant that ordinary English just doesn't have. Except sometimes; one example is the t in Gatwick, which just about everyone uses a glottal stop for.
And the vowels are different, usually longer. "down" is "dahn", "out" is "aht". It's hard to spell them phonetically, but if you're really interested, there's a good web site.
It's also a way of talking. When I'm telling about something that happened, even today I drop into the present tense, which is the Cockney way of telling a story. When I get into it, I start bringing in rhyming slang, and when I get really excited, I start droppin h's, g's and doin the glo'al stop. An I starts talkin a bit quick, like, and I says "dahn" and "trahsis", and I waves me 'ands around a fair bit, yer know what I mean?
People don't "say" something, they "turns round and says" it. You never says "very", you says "bleedin" or "bloomin" and instead of "very very" you turns round and yer says "bloody".
And then there's the emphasis words; bloomin' and ruddy, bleedin', flamin' and bloody. And the phrases you put in from time to time, would I lie to you? Stand on me. Gordon Bennett. I don't actually have the faintest idea who Gordon Bennett was. You learn this stuff from your parents and peers.
And there's prolly other stuff. I don't fink about it, I just do it, it's what I learned when I was a saucepan lid.
And while I was doing this translator, I was assuming that there couldn't possibly be a word for "computer" or other things that have only been around for 20 years. Then I 'eard meself (and it ain't just me). I call a computer a "box o' bits", and a manual is the "book o' words". Anything else complicated is "the doings" or "the doobry".
Dick Van Dyke in Mary Poppins make a good effort, but to me he sounds like an American trying to sound a bit Cockney. Good try, Dick, but no coconut.
There seems to be a widespread belief that Cockney rhyming slang was invented so that the police wouldn't understand what they were saying. That's hilarious; if you believe that, I have a bridge I'd like to sell you! The police would learn it as fast as it was invented. No, it's just done for fun, and because people like to feel like insiders, and because language always does that. Indeed, as I went round the web to set up this page, I found rather a lot of cobblers; non-cockneys rabbitting on about Cockney make a lot of silly mistakes.
I also discovered the origins of some words I use. "Bread", for example, I'd always assumed that was American slang. But it isn't, it comes from "Bread and honey", money. I've always used "Barney" for fight, but I hadn't realised that was from "Barney Rubble", trouble. And I knew that "taters" meant cold, but I didn't know it was from "Potatoes in a mould". And I knew what a "blowing a raspberry" was, but didn't know it came from "Raspberry tart". When yer a saucepan lid, yer just learn this stuff like a sponge. Gertcha!
If you want to hear *real* Cockney, get a Chas-and-Dave CD, a style of music called "Rockney" that I'm not even going to try to explain. "The Best of Chas 'n' Dave" or "Boots, braces and blue suede shoes. Or listen to Thrupenny Bits by The Hampton Cobblers. Or watch "Only Fools and Horses". Or "Till death do us part". Or go to Cockney On Line
Or if you're seriously interested in what academics call Estuary English (as distinct from BBC English, Standard English, Queen's English or Oxford English, which is the "official" British pronunciation, that hardly anyone speaks except BBC announcers, and not even them these days) then the articles here will tell you a lot about pronunciation, vocabulary and tonal speech styles. But although there are some similarities, Estuary English isn't Cockney, there's a huge difference. Well, there is to my ears. Anyway, if you read some of those articles, you'll get a much better idea of what Queen's English, Estuary English and Cockney are all about.
First a warning. Once you scarper down these links, you've entered a new place. You've entered the Cockney Internet. Dickie birds don't mean the same as what you fink.
Until you can get to London for the real thing, here's Diana the bloomin' Valkyrie's web site, translated into Cockney. You can browse it, just like you would normally.
Or you can go look at someone else's web site, Cockney version. Cor lummee! Diana the Valkyrie has translated the entire internet into Cockney for you, so you can browse around as per usual, but everything will be in Cockney. Gordon Bennett, it's the dogs bollocks.