I have written a few things on this topic and here they are.
Confused about ESL, ELT, TEFL, TESL, ESOL, TESOL in Korea
Attempts to see what these terms mean to people. If anything.
[The comments are fascinating]
South Korea is an EFL situation
One the potential to use “EFL situations” as an excuse
Yeajin’s EFL World
All about one student and her experiences and English needs and level
Beyond #ESL and #EFL: Newer Categories in English Teaching
Not totally serious attempts to categorize contexts and create new acronyms