How does cross-cultural communication work?

I was reading a book about how Commodore Matthew Perry opened up trading in Japan, and told them he would be back by the next Spring for their answer to the American demands. However, the book doesn’t exactly say HOW he was able to tell them when he would return. How did they communicate with two totally different languages? Japan didn’t even have many foreigners living in Japan at the time, so wouldn’t really have that much knowledge about English, and I’m guessing that Matthew Perry didn’t have that much knowledge of Japan since it was isolated and not open to any foreigners… How does any cross cultural communication occur anyway, when two cultures with 2 different languages meet?

Usually it goes like this:

Culture A meets culture B on its home turf
Some trade exchanges between cultures A & B
Because it is mobile, Culture A assumes superior status to B and starts cheating
Culture B takes offence and slaughters a cheater or 2
Culture A proceeds with genocidal policy against Culture B.
In this process, language barriers and cultural conflicts are resolved for the most part, and harmony reigns.

At least that’s how WE do it. : )