nradov parent
MUMPS was originally developed in the 1960s for use on minicomputers that had maybe 64KB RAM. At the time it was a lot more important to keep code size small, hence the single letter commands. Readability wasn't a concern then but it sure looks like a mess today.
It's hard to imagine it's an improvement over just the raw assembly.
Imagine harder. It was an enormous improvement over assembly language. Not so much for the basic coding but for the portability and built-in persistent data structures. MUMPS has an excellent "NoSQL" database built in which is a pretty good fit for a lot of healthcare use cases.