history: I studied very hard for my ESL certification, and was sure I would pass the test going in. I recently took my ELS certification test. I studied really hard_comma_ so I'm sure I passed it. What's ELS?
current: Sorry, ESL. It's English as a Second Language. It just means I am certified to teach students that don't speak fluent English.
next: Ah, gotcha. A few of my friends teach English to Chinese students online and I think they have taken ESL courses