The four-letter k-word slur for Jews is not blocked. Maybe that term has fallen out of favor among anti-Semites. As a Web-enabled person of Jewish descent, I'm subjected to occasional doses of anonymous venom, but that word has never come up.
How commonly used a slur is seems to be a key factor in Google's censoring decisions. In the post-9/11 United States, we've seen a rise in hateful language aimed at people thought to be of Middle Eastern descent. Perhaps in response to that trend, Google search refuses to countenance the seven-letter r-word and the nine-letter t-word that begin with rag and towel and are used as ethnic slurs.
One unintended side effect of this policy is to prevent users from directly voice-searching the excellent coming-of-age film Towelhead starring Aaron Eckhart, or the novel it was based on. A search for "t******** movie" will not return the film on the first page of results, the algorithm recognizes it as the nonsense search "t movie."
The six-letter f-word used a slur for a gay men is censored, and I assume that the shortened, three-letter version of that word is blocked too, though I couldn't get my phone to recognize it. Likewise, the ten-letter c-word (whose last six letters rhyme with "trucker"), used as a homophobic slur, is blocked.
The four-letter d-word referring to gay women doesn't get censored--perhaps because the term (in British English, anyway, it's commonly spelled with a "y") also has nonhateful meanings ("ditch" and "levee"). Or perhaps the word has been appropriated by the lesbian community as a prideful way to refer to themselves.
Google does seem to look askance at misogyny, blocking the five-letter w-word for "prostitute" as well as the five-letter b-word for "female dog."
Many other common slurs seem not to have prompted Google to ban them, but we see no reason to mention them all here; just use your imagination.
Though we reached out to Google to ask how it decides which content to block in voice search, we have yet to receive a response.
People have tried to define and quarantine naughty content since time immemorial, and such efforts (and the debates they spawn) often prove to be messy and contentious. As it turns out, Google--a multinational corporation with near-unlimited resources--is just as confused as everyone else.
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