[BiancaDelRio]

> Does ESL stand for English as a secondary language ?

I believe so.

I picked up this usage (ESL as a descriptor of person) from forums and boards around the internet. Not sure how correct it is.

[haZard_OS]

It is accurate and also still in use in academia. In every educational institution I have worked, "ESL" is used both verbally and in digital records.

[reaperducer]

It's been in use for a long time. I remember seeing it in the 70's in colleges that taught immigrants English for free in night classes.