Jesus wept!! It's not confirmed we are in talks with him yet, never mind he has not actually been offered the job and he is getting slagged off!!
Never managed outside of Russian - ok, Fergie had never managed outside UK, Kopp had never managed outside Germany before Liverpool, Wenger had managed in a crap league in Japan, Bruce never outside of England, and Mourniho started off as a translator!
Slutsky has managed the top team in Russia alongside running the national side, think that qualifies him to run championship club
His English may not be perfect but sounds like he has been studying English since coming here, has lived in London a while now, and at a guess the interview (if he has actually had one) would have been carried out in English and not Russian. I think it's fair to say he will have a decent grasp of the language.
At least give the guy a chance