Just to reiterate, NSLI-Y itself is a scholarship given by the US State Department, however the brunt of NSLI-Y field work is done by various implementing organizations. Once you receive a NSLI-Y scholarship you will be directed down to an implementing organization who is then in charge of scheduling and running your program in accordance with NSLI-Y scholarship goals and guidelines. Of these implementing organizations, American Councils is the largest, and are also in charge of the entire NSLI-Y scholarship’s general administration (such as the application process).
A variety of factors influence who your implementing organization is, such as what your target language is and how much experience you have. Within implementing organizations, different locations may be offered based on language/cultural exchange experience and other factors. Last year for China Summer, American Councils took students with more experience in Chinese, while more beginning Chinese students were assigned different organizations. Then within American Councils, Nanjing was the most advanced, Xi’an intermediate, and Suzhou more beginning. Lastly, within locations it’s common for students to be split up even more: Xi’an split us into beginning, intermediate, and advanced. For me, I was ultimately categorized as beginning of the intermediate of the more advanced (a lot, I know!). For China Academic Year, it seems Changzhou is for beginners, Taiwan intermediate, and Beijing advanced.
I say “categorized”, but placement does not necessarily indicate your true skill level (nor does it limit you in any way!). Much of the placement process takes place way before any true language testing (i.e. OPI) takes place, and is based on your application responses. Within American Councils, classmates with the same Chinese experience were placed at different locations. I actually only had one year of Chinese language experience (compared to the 3+ of everyone else at American Councils), but was placed in Xi’an with American Councils due to having travelled a lot to China in the past. Regardless of where you’re placed, you will find similar people, and you will still be able to improve as much as you work.
Anyway, hope this was helpful in better understanding the (sometimes mysterious) workings of NSLI-Y!