One of my favorite subjects! I love accents, words and everything linguistic. One of my personal weird hobbies is to imitate foreign dialects, syntax, sentence structure, and any verbal peculiarities. I can do pretty much any accent in the world, but my American accent comes out by making the vowels sound a little flat when pronouncing a word I haven't heard spoken before.
British accents are among my favorites because of the tremendous variety within a comparitively small space. Cockney English is probably the most fun to do, but I also love many Scottish accents for the way they flow. And then you get to Nairn and you have to speak out of your nose
My all-time favorite is Caucus Russian. For some reason, just speaking it makes you feel like you have a glass of vodka, especially when you use the syntax in English. I also like German, but I don't know all the regional accents that well. I mostly just imitate German war vets on documentaries.
Oddly enough, the accents I have the most trouble with are American accents, probably because of my own slight drawl. I'll often slip in an exaggerated vowel or a
ya'll or
fixin' to when I try to emulate Yankee accents.