The investigation carried out on behalf of the Civil Aviation Authority (CAA) found there were hundreds of incidents of miscommunication involving commercial aircraft in the UK airspace over an 18-month period, Sky News reported.
In one incident, a pilot taxied on to a runway at a Midlands airport without permission.
Another mid-air event involved confusion over left and right on an approach to Manchester Airport.
The authority commissioned the independent review to assess whether there were any dangers from these incidents. It identified that there was a risk of "serious" accidents at home and abroad.
A total of 267 incidents that required reporting, called mandatory occurrence reports (MOR), were based on language problems during the period under examination.
The report said that cheating in exams, corruption and inadequate testing was partly to blame.
Rather than being examined, the report found some foreign language speakers had been granted certificates of English proficiency on "sweetheart" deals, through "handshakes" or "via friends".
The research, by academic Dr Barbara Clark, found "alleged evidence of cheating", whereby a candidate had passed the tests after just 10 days of studying -- a "nearly impossible" achievement.
Some pilots flying in UK airspace "appear to lack the minimum proficiency in English", the report said, while air traffic controllers outside Britain do not always have sufficient English to communicate with pilots even though they have been obliged to meet an industry standard since 2008.
For the safety of the UK travelling public, it is imperative that all pilots and controllers working in international aviation have the proficiency to communicate clearly and succinctly in all situations, routine and non-routine, the report said.
"Language-related miscommunication, including lack of ICAO (International Civil Aviation Organisation) proficiency standards, certainly has the potential to be the cause of serious incidents or even accidents," it said.
To work in international civil aviation, pilots and controllers are required to gain a Level 4 qualification in English from the ICAO.
But the report said it found there were enough non-UK pilots and controllers with below-standard English skills to give "grounds to suspect cheating on aviation English exams".
A CAA spokesman said it was discussing the findings with the UK's Department for Transport.
"We will be studying this research and will work with ICAO, other international regulators and the wider aviation industry on any actions that can help (to) enhance safety," he said.