I'm bilingual and have learnt several European languages over the years. In both my academic and engineering roles I have worked with many non-native English s

I'm bilingual and have learnt several European languages over the years. In both my academic and engineering roles I have worked with many non-native English speakers. When I have to speak in one of the European languages I realize how hard it is to express technical materials when you are not fluent in the other language. Makes me empathetic for my non-native English co-workers. Since you are asking the question on HN, I assume you are working in an IT area. For that reason I suggest that EN-US should be basis for your "international" English. Simple reason being that the vast majority of resources are written EN-US, so why fight it. (I say that as an Aussie and a pedantic preference for EN-AU). In order to overcome the differences in verbal communications, I suggest taking guidance from Amazon and focus on being documentation-centric. Ensure that a fluent English writer edits the documents. That way, non-native speakers can take their time to unravel materials and also improve their English. I also find that it builds bridges to learn, to at least tourist level, the languages of your co-workers. Take time to learn about their customs, etc. It is also a good idea for persons who habitually speak fast to slow down. Give people more processing time to grok what is being said.