I think teachers should have a firm grasp on the language of the country in which they choose to teach. I think all teachers should be clear and concise and easy to understand. I think all teachers should have good large vocabularies, and be able to put together a simple, compound, or even a compound/complex sentence in front of a group of people who gathered expressly to listen to him/her. I think a teacher who can not communicate properly, professionally, and well, should consider another kind of job.
As should a President.