Question #169:

How is “speaking internationally intelligible” within the aeronautical environment provided? Paraphrase: What do pilots do to speak English according to the international standards? (What proficiency is required?)

Answer:

According to international standards both pilots and ATC must have the 4th level of ICAO. It means the they should use standard phraseology, speak with the rate of speech not more than 100 words per minute. In order to maintain or improve operational level pilots must pass refresh courses each 3 or 5 years.