I've had projects where I've been able to understand everyone just fine, but the non-native speakers who were from different countries couldn't understand each

I've had projects where I've been able to understand everyone just fine, but the non-native speakers who were from different countries couldn't understand each other. Luckily, it was a minor inconvenience that all of us could easily handle, but I could see this being a valid reason in some circumstances (e.g. jobs that require a lot of time spent on the phone)