ICAO (International Civil Aviation Organization) English Language Proficiency refers to the standardized language requirements for aviation professionals, particularly pilots and air traffic controllers, to ensure effective communication in the global aviation environment. The ICAO has established a six-level proficiency scale, ranging from Level 1 (Pre-Elementary) to Level 6 (Expert), assessing an individual’s ability to use English in both routine and non-routine situations. This proficiency is crucial for maintaining safe and efficient air traffic operations, as English is the international language of aviation.