There are many factors that one should take into consideration when sending messages internationally. To start, languages are not the same and the cultures vary from one another. People interpret things differently abroad. Being someone that comes from Europe, I can relate to both the American and European way of communication.
From my own experience, I would say that people in Europe are a little more cautious when speaking or reading a document or message; in a sense of translating that document or message word by word. European people also tend to be more sensitive and they tend to take things very personal. It is very important that when sending messages internationally, you take their culture, language and tradition into consideration. When individuals do not take that into consideration, they might get offended with something that you might mean good. When sending a message in English to French people who do not speak English fluently, the French will translate the message word by word, which what you meant in English might mean something else than what they translated it to. Europeans also tend to use a lot of phrases and idioms that if Americans translate it word by word, it wouldn't mean anything that makes sense in any European language.
From my personal experience, when I send messages to my friends abroad, I avoid using too many phrases or idioms because I know that they will misinterpret. However, if I know that the person I am sending a message to understands the English language perfectly, then I will be confident enough to say anything in English. The English language can be very difficult for a foreigner. People in the United States might put a correct sentence together in English but in Europe they will put it together by the way they translate it, which it might not make the same sense that it does here. These particular things that I mentioned above have a lot to do with the culture and tradition of a particular European country.