JK and Linguistics

In preparation for HP7 Part 1, I have been rereading (again) the series. I'm a little behind, only just finished Goblet of Fire, but I had a lot of school work this week. I've been borrowing the books from my roommate, who purchased them in Great Britain. I'd read the British Prisoner of Azkaban before, as I own it, but I'm really enjoying reading the entire series in British English. It makes for a much more interesting read, being, as I am, so fascinated by various English dialects. I love the variants in spelling, lexicon, and syntax:

Spelling
Most spelling variation comes in the vowels (not all, just most). British English retains older spellings, although every once in a while we see them in American English as well. A few examples . . . 

British     American
Grey          Gray
Pyjama     Pajama
Colour      Color
Defence   Defense 

Lexicon
These might be my favorite differences. There were some I already knew, but others were fascinating to me. These were the ones that jumped out most:

British         American
Jumper         Sweater
Puddings      Desserts
Revise          Study
Scarper        Run away

Syntax
Syntactic differences are intriguing because I would assume that Standard American and Standard British (or RP) would have basically the same syntax. I usually think of syntactic differences appearing in nonstandard dialects. However, there are a few.

British                 American
V+O+VP               V+VP+P+O
Catch you up      Catch up with you

The best syntactic difference is one that I think we will eventually adopt in American English. We have already begun changing some of our past participles to be spelled this way, and it won't surprise me if our past tense verbs will too. We just haven't made it there yet.

British      American
Learnt        Learned
Burnt         Burned
Leant         Leaned

British English also, apparently, does not approve of the Oxford comma. On this point, I disagree with their choices.