Linux-for-Rust or Rust-for-Linux

> Then why is it so hard to understand what khim is actually saying?

Because English is a foreign language for khim? Of course it's more difficult to express yourself clearly (and/or succinctly) in a language that's not your native language. I can express my thoughts pretty fluently in Dutch; English is significantly harder, even though both languages are pretty closely related. French is almost hopeless even though our education system tried pretty hard making us learn that language. German is closer related still, but while I can read it a bit I can't write or speak it at all (other than trivial things like "Zwei Bier bitte"). If I try to express something in French, chances are French-speaking people will think it's difficult to understand too. And it's more difficult for things that are expressed differently in native versus foreign language.

How much study of Russian would you or I need before we are as proficient in it as khim is in English? Will khim wonder why he can't always understand our reasoning expressed in Russian?

I think you're thinking of the linguistic relativity, also known as the Sapir–Whorf hypothesis (and other terms), and more specifically it seems you're thinking of the strong form which says that language determines thought and that linguistic categories limit and restrict cognitive categories. Modern linguists don't accept that hypothesis anymore (or at least that stronger form).