Rights of Publicity For All
One right of privacy - also known as the right of publicity - is the commercial appropriation of someone's name or likeness. It happens when the name or likeness of someone is used without consent to gain some commercial benefit, such as when a photograph of a person is used in an advertisement without the person's permission. That is why model releases are so important. It is evidence that you have the person's permission to use his image for certain purposes.
So what do you do when you travel to foreign countries to photograph the people there? Do you need a model release? What if the people don't speak English?
Nevada Wier has published thousands of travel photographs from all over the world. Her advice in her book, Adventure Travel Photography, is:
If you plan to use your photographs for publication or stock, I think it is wise to have signed model releases from any people you photograph in a foreign city, no matter what their nationality or what the shooting situation is. (Even though lawsuits aren't currently common in the rest of the world, this might change.) Translate your release forms into the language of the country you'll be traveling and photographing in. In more remote regions it is a bit trickier to get signed model releases, and not always appropriate. People may be suspicious, confused or frightened if they're asked to sign a piece of paper. Use your common sense.
I couldn't have said it better.
Take my advice; get professional help.