You'll find it stated in a number of places that the working language of
the IETF is English. Well, yes.
What is not stated is how good that English has to be to participate
fully in technical discussion to get the most out of IETF participation.
I would suggest that an IELTS score of 7.0 or higher, or equivalent,
in all categories is a good indicator of being able to participate fully.
If someone is unable to achieve that level, they, and everyone
interacting with them, will find written exchanges very frustrating,
to the detriment of discussion overall.
If we're going to write RFCs codifying behaviour, we can codify this, too.
Lloyd Wood
http://about.me/lloydwood