Hello Simon,
If money is not a problem, ThoughtEguity Stock Footage comes to mind as does National Geographic Digital Motion. You might have to give them a call and get a sales representive to help you with your searching.
My apologies on not listing any websites but my HD crashed last week and all my weblinks and favorites were lost…
Another alternative, and this may or may not be cheaper, is to hire some local acting talent and shoot them yourself. Contact a costume shop in your area to get right apparel for each nationality and with a little searching online you can find pronuncuations for the word “hello” in different languages. Even cheaper would be to shoot head shots of the acting talent so that you have less to rent from the costume shop. If acting talent pool in your area is underpar, you can contact community centers, churches and even lawyers that handle immigration cases and see if they can put you on the right path to find the nationalities you need.
If you can, see if you can get names and numbers of court language interpreters in your area. We have use them on commercial projects when we need two or three language versions of a commercial we are producing.
Sidenote: I was on a promotional shoot a couple of months ago to get reactions from a local lawyer who won a community service award for her pro-bono work she has done for years for immigrants in our area. It was there that I met a man she had help who had a strong, distinguished voice with a beautiful russian accent. After chatting with him for a bit I got his name and number for futher use.
Hope this helps you out.
Eric Christians
Rochester, MN