Is it one of the requirements to teach English abroad? In most cases you don't have to be able to speak the native language to teach English abroad. Many schools may even prefer that you don't have a knowledge of the local language, as they want you to converse with the students in English. But how can I teach them you may ask?
Well actually translation is just one of seven methods of teaching. It's the oldest method, but it's not necessarily the best. Words and meaning can be taught through other means such as: using pictures, body language, objects, synonyms, antonyms, kinds of and more.
Learning the local language is a good idea though for outside the classroom. Having a knowledge of the local language will help you get around and connect with your new foreign friends.
Are there any exceptions to the rule? Sure, I have seen some schools in Japan and China note that they would prefer a teacher with a basic knowledge of the local language, however it is not the norm.