[gala8y]

I would really rather read his guide to learning English.

[vaskebjorn]

Be born into a noble family with english speaking governesses.

[oytis]

He was exposed to English from the very young age, it's basically his native language

[nephihaha]

Sort of. When I hear Nabokov speaking, he sounds like he has an unplaceable regional accent, as opposed to a "foreign" one. His writing in English is fluent, but can have a few tics in it — he repeats certain fancy words, and he tends to avoid slang.

By the way, the last tsar's daughters reportedly picked up a slight Irish accent from one of their tutors. He was sacked and replaced by someone more pukka.