This thoughtful post from Quartz analyzes interpersonal dynamics in the modern hybrid-culture office --- say the Tokyo branch of a New York bank. Ideally, non-native speakers should benefit from time spent around native speakers. And as a general principle, that is indeed fine enough. But the general runs aground on this particular: English's global dominance has facilitated a monoglot bias among (relatively lazy) native speakers.
The monoglot speaker - the intransigent monoglot speaker, imperiously if implicitly demanding that all come to him or her -- poses two challenges.
The first is attitudinal: never having faced the humiliating infantilization that wading into a language as a student represents, they exhibit a lack of empathy for the challenge that their non-native-speaking colleagues have faced (and likely done quite well with).
- Avoid overly idiomatic expressions. "What's the ballpark figure?" is much harder to parse than is "Approximately how much are we talking about?"
Language is an inherently social tool - arguably the most social tool ever invented. It can foster belonging and identification, but just as easily relegate someone to a less-desirable out-group status. As the post notes,
The inability of the traveling native English speaker to refrain from homeland idiosyncrasies, subtextual dexterity, and cultural in-jokes has been found to result in resentment and suspicion.... a loss of professional stature when having to speak with those who are not only comfortable with the language, but who appear to vaunt the effortlessness with which they bend the language to their will. And [non-native-speakers] suspect that the offending expat uses this virtuosity to gain unfair advantage in the workplace.
It can also hurt your business. The post recounts how at a global partner meeting:
International partners would hold back from actively contributing to meetings where his British and American partners dominated the floor. Following the meeting they would seek one another out to discuss matters between themselves in private.
Be courteous. And a good role model - not the ugly American/Generic-Anglophone abroad. Louder does not mean clearer. Tailor your speech to your audience -once you've taken the time to consider them - and everyone comes out ahead.