Bele: It is obvious to the most simpleminded that Lokai is of an inferior breed.
Mr. Spock: The obvious visual evidence, Commissioner, is that he is of the same breed as yourself.
Bele: Are you blind, Commander Spock? Well, look at me. Look at me!
Captain James T. Kirk: You are black on one side and white on the other.
Bele: I am black on the right side!
The American who IMHO performed the best English accent I’ve heard? Forest ****ing Whitaker.
Dayum.
Or for that matter Barry Bonds. Grew up in the richest, whitest areas of San Francisco and, in the words of his biographer, Jeff Pearlman, spoke “like Eddie Murphy doing his white man accent on Saturday Night Live.”
For that matter, if people want to think of Iranians as a race, whenever my dad speaks he still sounds like he’s fresh off the boat even though he’s lived in the US for thirty years whereas I sound like a grew up in a Connecticut country club and my last name has a roman numeral attached to it and I have a wife named Sydney.
I can never find a link for this now, but back in the 1990s I remember reading about research that was carried out at the University of San Francisco which tested Americans’ ability to identify a speaker’s race merely by the sound of their voice.
What I recall about the research was that the African-American speakers were deliberately chosen for not having an identifiable AAVE accent. Despite this, a very very high percentage of subjects were still able to distinguish the black speakers from the white speakers.
I can’t offer any further information about how the study was conducted nor do I want to speculate on the reason behind the findings, but it is interesting.
Personally, I don’t care about evidence or reasoning or my personal inability to notice it unless there’s a video. If it ain’t a black chick singing, I ain’t listening to “Great Gig In The Sky”. 
Slightly more on topic: OP, given the lack of evidence for any particular gene representing how people speak, don’t you think it more reasonable that certain racial minorities have certain speech affectations because of cultural expectations/norms, rather than racial ones? I mean, we all have a basic idea of how black people speak, accent or not - you think black people don’t pick up on that?
Language is quite clearly transmitted culturally, not genetically. Given that, it would be extraordinary if accent was genetically determined. I think it’s just a bizarre proposition. Even if it’s true that particular ethnic groups have distinctive forms of speech, that still wouldn’t suggest a genetic factor, any more than an ethnically-distinctive religious denomination proves that religious denomination is genetic.
OP types white.
Presumably, the OP meant ‘nuance’, possibly.
Hmmm… Black kid, white neighborhood, not bred for colder territories…
I’m willing to bet Grant Fuhr and Wayne Simmonds disagree with the sordid OP. Of course, Grant was half black and adopted, so does he say “Eh?” more than Wayne does?
White people have the greatest diversity because it is a social group that grows more inclusive by the decade, nothing to do with genetics.
Weakest genes is scientifically meaningless, might as well say they have the weakest lifeforce.
I recall watching a comedian at some point back. Asian looking guy and can’t specify his actual background. Then, he spoke and my mind went, ‘hey, that ain’t right.’
Pure backhome, cornbread and butter beans accent.
He grew up in Tennessee and spoke Tennessee.
Thought for a second you were going to rick-roll us 
They have the most Midichlorians, though.
I know a guy like that also; You see him and you think he’s probably some FOB Chinese guy, or maybe not quite FOB, but still an immigrant.
Then you actually talk to him, and you find out his name’s Roy and he’s from Alabama, and if you didn’t actually see what he looks like, you’d think he’s some tobacco dippin’, beer drinking redneck from Alabama.
I bet it’s not a matter of accent, but rather some combination of word choice, idiom use and grammatical construction. You could have Anthony Hopkins and George Clooney read the Smokey/Craig scenes from Friday in their normal voices, and it would still be very clear that the characters are black. I bet that even in non-accented black people, there’s still some kind of residual pattern that’s easily picked up.
Henry Cho. Born and raised in Knoxville, TN.
My brother is his non-comedic Arkansas equivalent (I don’t have much of the accent but my word choices occasionally veer southern).
All it really takes to prove the OP wrong is just listening to anybody from the UK. The challenge is simple. Take a random UK (or Australian or New Zealand or whatever) voice sample and identify the race of the speaker.
My first response to reading the OP was to Rickroll him. I mean, it would be the first absolutely justified (and helpful!) time.
There was also a song from the 80’s that I never saw the video but presumed the singer to be big time Motown and turns out to be a white kid with red hair. In that case, it wasn’t the language, it was the power of his voice.
I still think that race has nothing to do with it. A combination of education, word choice, culture of upbringing and probably a whole lot more.
… new to the Internet?
Well, sure, but “A Nuisance of Blackness” *definitely *sounds like a Ngaio Marsh title.