I think for many non-natives it is a challenge to get the ideas across. My daughter will be dual mother tongue (Finnish/English) and I am interested to see how it will affect her thinking. My father is a non-native English speaker (although you would not know it) also and definitely seems to understand and express in slightly different ways to most.
Many non-natives prefer to write as it gives the space to think and review and perhaps, it allows the space for shyness and introversion to be less of a factor. I like sending emails to bosses too, mostly because I just don't really want to talk to them though. ;)
I agree with that being non-native & introverted that makes writing even more useful. It gives time, space, room to improve. I used to write a lot in English (my second language) and really started to like writing, and have recently found out that when I write in my native tongue (Dutch) writing is even nicer and easier.
It is often the case as it is kind of like running uphill and then for the race, you are on even ground. By exploring yourself through a foreign language, you see with different eyes.
Yes. Reminds me of a quote (not sure by whom)... the more languages you speak, the more people you are. Really impressed me when I was young, to hear that.