Youtube is an excellent resource for writers need to get the accent, vocabulary, and phraseology of their characters right.
Have a character speaks upper-class or POSH British English, here’s a good resource:
youtube.com/watch?v=A0-Dex6X9m4
And if your character is from the Southern U.S., check out Amy Walker:
youtube.com/watch?v=R30D7v5RRSY
And here’s the talented Amy with a sampler of many accents:
youtube.com/watch?v=MBtLxuv0-u8
Of course, in writing, getting the word and phrases people use matter more than the intonation.
There’s a host of other videos on similar topics. Some can get funny. Here are Germans trying to say squirrel.
youtube.com/watch?v=0FRD4uq1mVw
Of course, native-English are likely to stumble over any of the many German words with more than four syllables and what is for us way too many consonants.
–Mike Perry
The most helpful advice I’ve found to date on the subject of accents and dialog comes from one of my favorite SF writers, Tobias Buckell:
But by the time I was writing that novel I’d written a number of short stories experimenting with different ways to portray the rhythms and sounds I grew up hearing around me. I chose not to use a direct phonetic spelling, like many do when trying to depict a dialect or patois, because I felt that would slow readers down and distract them (I still struggle to read some James Herriot at times). If a word had an English analogue, then it would be spelled the same. It was structure and grammar that I aimed to replicate the experience. - See more at: graspingforthewind.com/2007/ … npVaz.dpuf
(from http://www.graspingforthewind.com/2007/11/02/sf-with-an-accent-an-interview-with-tobias-buckell/ )
I definitely agree with him about James Herriot, whose books I otherwise adore – and I found that Buckell’s way produces a clearly distinct mental voice for his characters, one that for me doesn’t slow me down and rip me out of the story. Your mileage, of course, may vary.