As the number of planes in our skies continues to grow, so the need for safety becomes even more important
An ICAO review of 28000 incident / accident reports has found that over 70% of the problems were caused by language.
ICAO standards now demand that all pilots flying internationally and all air traffic controllers providing services to international flights must have a minimum level of English.
This level of English is known as ICAO Operational Level 4. The language descriptors (developed by ICAO) can be found here.