The use of language for verbal communications adds the dimension of pronunciation within any language because of regional differences in speech dialect. There are also the issues which arise from variations in English language proficiency amongst the many who must use it for radio communications in respect of international air transport but who do not have it as their first language. These users can reasonably be expected to have a wide range of proficiencies in the use of it.
Abbreviated English
Use of Standard Aviation English phraseology is a major contribution to the reduction of ambiguity in Aircraft/ATC exchanges and supports a common understanding among speakers of both: