At the last Email Insider Summit I was invited to sit on a panel to discuss what it takes to go global with your email program. The short answer is: it takes a lot of planning, extra time and budget and preferably local resources.
At my previous company, my team was responsible for sending out a newsletter to 12 different European countries -- in the native language. Our corporate headquarters (located in Ottawa, Canada) would come up with the main content for the newsletter, but each country had the chance to add local news. And then the fun began...
We would send the final copy (in English) to translators in each of the different countries. Even the UK version had to be "localised". We couldn't do one Dutch version for both the Netherlands and Flemish part of Belgium, because even though the language is the same, we have different ways of saying things. The same for the French part of Belgium, the French part of Switzerland and France. And for Germany, Austria and German-speaking Switzerland.
Once the copy was translated and localized, we would send it for review to each country and they would approve or make corrections.
We would then code each of the emails separately, only to find out that what you can say in English in two lines, you need four lines to say the same thing in French... So the design didn't work anymore, of course.
And then there was another obstacle: the email platform that we used did not support foreign characters, so we had to manually replace all the letters with accents with their HTML codes.
And when we sent the final version of the email out for final approval by the countries, we would learn that we can't e.g. use a picture of an Asian-looking woman for a German audience. Or the screenshot would have to be in French...
In the end we had it all figured out, but getting there was a slow and painful process.