I have taught ESL for years. I’ve taught in a classroom with many levels of students and one teacher. That was a tough one but I had developed strategies to cope. Learning there does not happen as quickly as it does in a classroom with students all on the same level. I have also taught over Skype for pay, and I currently have a Skype student who I teach for free. For a couple of years I taught in Delaware for a nonprofit group working with ESL adults. The paid teachers had all had ESL certificates, and they went to a real college or university to get it. A non-English speaker can also take ESL classes in university, which of coarse means that there is a trained teacher to teach you. I haven’t begun to touch on ESL in elementary through high school, but there is a growing need for that as well. Working as an ESL teacher in any public or private school system requires a teaching degree and ESL certificate. As for myself I do not have a teaching degree. There are companies overseas who are always looking for native English speakers to teach their students, and you don’t have to have any sort of ESL certificate for that. They are a bit of a challenge to find but they are out there. The biggest problem with it is the fact that you have to work crazy hours in the middle of the night and it is always part time.