Carolyn
It's been more than 30 years since I saw the film, but if I remember correctly, it takes place in a socialist society of the future. Because Russian--thanks to the Soviets--is the language of socialism, teenagers speak in a slang based on that language. They refer to their friends as "droogs" (from Drug, the Russian word for friend). Elderly folk are called "starry loodies" (from starie liudi, or old people). The milk bar where they hang out is called the Korova (cow), and when they like something, they say "horrorshow" (khorosho, or good).
The hero is subjected to an experiment in behavior modification of the type that Harvard psychologist B. F. Skinner was promoting.