They are all right, and sometimes, we just have to forgive each other when we accidentally offend each other. Tolerance and acceptance is important :)

Just be open minded and everything will be okay.

All of the first three points are right. :-)

huanity is the constant stuff that has never changed for thousands of years, no matter where we are born on this planet, we are basically the same in the term of humanity. So in my perspective the more profound we are able to understand about humanity the better we can understand the way people talk or behave from every part of the world no matter which background we are from.

The three options are all needed to remove cultural barriers. Being fluent in a second language and cultural tolerance make positive influence on intercultural communication.