I taught EFL abroad for many years and loved the opportunities for travel. It can also be a very lucrative profession in some places, like the Middle East and Taiwan. However, there are certain challenges teaching abroad. These may include lack of structure in the program, depending on the school where you teach,and difficulty accessing English language resources from the community, such as newspapers and libraries. In this the internet can help, but sometimes photocopying worksheets you make is restricted or electricity fails and the lesson you had planned turns into thinking on your feet. This can be exciting or stressful, depending on how it works out. Also, in a monocultural class, students are always tempted to speak to each other in their own language and not practice expressing their ideas in the target language, which for the duration of the class time, is English. Practice makes perfect...
In the past few years I have been teaching English as a Second Language to international students and immigrants in Canada. This has other advantages and challenges. On the one hand, the students are highly motivated and willing to work hard. It is easy to access community resources, for the whole community speaks English and teachers can assign contact assignments,set up library resource assignments, and use newspapers, library books and guest speakers. Moreover, mixed cultural classes makes it feasible to create small groups of mixed languages, where the only way students can complete the task is by interacting and collaborating with each each other in English. Once they break the ice and get things moving, they appreciate getting to know people from the other side of the world, In fact, that's what international students have come here to do.
Challenges are the usual ones with teachers--keeping up with mixed level classes, balancing the mix of work at home and relevant and achievable homework with in-class structure, guidance and practice, and managing the personalities and various goals.
It is wonderful work with lots of room to be creative and incorporate the teacher's own interests into the curriculum, and grow with the students. I love the contact with the international forum and the intellectual stimulation. The work is varied and flexible, with lots of opportunities to develop it in your own way.