Pascal.

And yes, I know there are some people interested in it, like any retro topic.

I did not master the thing but I used to know Basic on a Commodore 64.

Not so useful anymore.

Clipper Summer 87
Z80 Assembler
Basic

😅

TestAlgo.

Isn't it, @inso, @mathieui?

This might be cheating, but 1990s era JavaScript. Used it to create a dynamic website with lots of logic in the browser, using something similar to JSONP to make queries using hidden frames.

All of that knowledge is, essentially, obsolete. JS isn't the same language any more (which is a good thing for the most part)

(There's also a bunch of proprietary languages for EIS systems I learned I wouldn't even remember how to use if I used them today. And some of them were needed in the same project.)

php and Java.

Edit: with work you mean corporate work. Right?

Actionscript 2. I still like to make games and programs in it, and they tend to be tiny and super compatible with every computer made in the last 25 years, but it has limits.

The syntax is nearly identical to old JavaScript so it's not entirely obsolete.

Perl.

I suppose I could still use it for sysadministrivia, but no.

(Turbo) Pascal
(VisualWorks) Smalltalk

Liked them both a lot, though 😀

PL/1. I even wrote an extension for it in 370 assembler when I ran into something it couldn't do.

Then I needed something done on a PDP11, and politely asked if PL/1 was available there. When my counterpart was done laughing, he suggested I learn C and if ever I got the chance, UNIX too (my uni ran RSX11). Wolfed my way through K&R, the Lions Book, and eventually the Dragon book. The rest as they say is history.