The site is written in a style I would call 'arts journalese', it is targeted at upper middle class people with a specific level of education and familiarity with the arts. The language used is not particularly complex, much simpler than you are capable of, but it will use vocabulary that is new to you, and will try to use it in creative and novel ways to attract and engage its readers; these will be difficult for you if you have had little exposure to natural English. I suggest you read some more straightforward journalism, such as local news, and read some advertising features and other down-market stuff first, then revisit NPR once you are more comfortable.