Obviously if you add a bunch of cutsey syllables at the end of every word you'll end up sounding like Ned Flanders. I don't think things are as totally traditional as the Canadians are making it out to be though (I've never been to Canada and only know a couple, so Ill leave it to them to confirm about Canadian English). I'm pretty sure they would call a highly technical person a techie (not to be confused with a Trekkie--a Star Trek nerd). And in the states we have nicknames for things that are diminutive but without adhering to the -ie formula. Football is pigskin or gridiron, basketball is hoops or b-ball.
What about
pop/soda/coke (all three terms refer to carbonated beverages/soft drinks)? Are they diminutives? What about text speak or chat acronyms? I have personally overheard people say the letters OMG (oh my god) and TTYL (talk to you later) in conversation. Yes, they were adults and yes, I did die a little inside when I heard it.
In British English (what I heard of it while living in Ireland, anyway), the formulaic -ie/-y/-er diminutives are more common. People watch footy or ruggers on TV, lots of people wear trackie bottoms (tracksuit trousers) and many "undesirable" youth wear hoodies (hooded sweatshirts/jumpers) and will occasionally do a runner (run away). In the office, we exchange prezzies at Christmas, but there was always a long boring prezzo (presentation) for the end of year results.
edited to add:
How could I have forgotten California's contribution to diminutives? Hella (meaning a hell of a lot of, but used as an intensifier... it's hella annoying).
