Because he fights
a Russian.
The Big Bang Theory Season 12, Episode 10
We came a-across
a-a Russian paper
The Big Bang Theory Season 12, Episode 10
Haven't you ever been told
how beautiful you are in flawless Russian?
The Big Bang Theory Season 1, Episode 2
a Russian paper that seems
to disprove super-asymmetry.
The Big Bang Theory Season 12, Episode 9
I speak a little Russian.
The Big Bang Theory Season 12, Episode 20