The clarinet is a pretty key component of Klezmer music, and just about every film about Jewish people in Eastern Europe seems to rely on that distinctive trill with the clarinet to set the mood of a scene at some point. How did it come to be such a central instrument of the genre?
There are two pretty strong fashions in Klezmer music; the earlier one had more fiddles, string bass, and often tsimbl ( cimbalom) , choices no doubt influenced by gypsy musicians. (Those distinctive trills are also done on fiddle, and tsimbl) But the very strong reed-and-brass band movement in the later 1800's, coming out Germany/Austria, influenced the newer bands...and of course the clarinet had a lot of popularity with jazz bands, too.
There were also real virtuosi, like Dave Taras and Naftule Brandtwein, who inspired others to play it.
You might want to cross post this to /r/musicology.