1. Yes and no and да и нет
What could possibly be easier? You might think that yes and no are the easiest words to learn in a foreign language. But in Russian it is not quite that simple.

In Russian, да can mean "Yes, you are right" and нет can mean "No, you are wrong". This can lead to a misunderstanding for English speakers when a Russian asks a negative question.

See how it works in Ruslan 1 Lesson 2 dialogue 1:

Иван: Здесь нет метро?
Людмила: Да, нет метро. Вот стоянка такси, а там автобус.
Иван: Спасибо.

In English this would normally have been:
- There is no metro here?
- No, there isn't.
But a Russian would normally say:
- Yes, there isn't. ("Yes, you are right, there isn't.")

This isn't just a pedantic point, it can lead to all sorts of confusion and could even have led to the end of the civilised world as we know it. Imagine Khruschev and Kennedy in the Cuban crisis in October 1962 if they had tried to sort it out on the phone without interpreters:

Kennedy: You are not going to press your button are you?
Khruschev: Yes, ....

Nikita Sergeyevich was going to say "Yes, I am not", but it was too late, JFK had already pressed his button...

John Langran, January 2018