In English, and beyond....
We carry books in a variety of languages, from the very popular (Spanish) to the more obscure (Urdu). We have 18 titles in Urdu text, all of which have circulated more than once. We have 247 Korean language books in the collection, many of them new titles, with varying circulation stats. Some have gone out multiple times, some not at all.
Because we have a floating collection, we do not have to assign books to certain branches around the city. This is a great thing for foreign language books because we haven't found any good ways to find out, in branch service areas, what languages are most popular. There is anecdata about this part of town being heavy with Russian speakers, and that part of town having lots of Chinese speakers. Spanish seems to be popular on all sides of town. The anecdata, however, often is rebutted by the fact that books in foreign languages are checked out in unexpected places. Doing a quick scan of the 35 books in Gujarati that we own, many of them have circulated multiple times in 2012, and in multiple parts of the city.
As far as sussing out hard data, it is difficult to come by. There are some statistical databases that use census data (so you can use census.gov as well) but it is difficult to navigate and, sometimes, doesn't provide the exact information you're looking to find. We keep trying, of course, with both our immigrant outreach librarians and the reference librarians who use both the SAVI database and census.gov with surgical precision.
About the books:
Some of the foreign language editions we have are single, signed copies of books by local authors, which are non-circulating and are hidden away in our Indianapolis Special Collections Room. If you're curious about the Finnish edition of Vonnegut's Sirens of Titan, you'll find it there.
A lot of the foreign language books we carry are by authors in their native language. However, we also carry popular English language authors in foreign translations. I was curious about this aspect, so I asked a few authors about their experiences having their works translated into different languages. I asked them all the same questions:
Do you receive copies of your FL editions?
What languages have you been translated into?
Foreign language editions, do you have them in your library? I want to hear your stories!