[1] Despite the seemingly limited focus, a course of ESP can have a wide-ranging impact, as is the case with Environmental English.
Aviation English is taught to pilots, air traffic controllers and civil aviation cadets to enable clear radio communications.
Many professional associations of teachers of English (e.g., TESOL and IATEFL) have ESP sections.
When doctors of foreign countries learn English, they need to learn the names of their tools, naming conventions, and methodologies of their profession before one can ethically perform surgery.
Some ESP scholars recommend a "two layer" ESP course: the first covering all generic knowledge in the specific field of study, and then a second layer that would focus on the specifics of the specialization of the individual.