Must a Developer Know the Language?

We were asked, "Have you ever applied for a software developer job where you didn't know the language?"

My story is not exactly the same as others might have, for several reasons, but I think it does answer the question.

There are two phases to my story. My first job developing software was at IBM, in 1956. At that time, I didn’t know any programming language, largely because there really weren’t any languages other than machine code. So, I spent two weeks in a closet learning my first computer language.

Actually, it was three languages at once: machine codes for the IBM 704 and 650, plus the wired “language” for the IBM 607.

The second phase of my story takes place some years later, when I became a consultant. In that role, I have helped many, many clients who were using languages I didn’t know—even though I knew quite a few by that time, including LISP, Smalltalk, APL, PL/I, COBOL, FORTRAN, C, Pascal, Simula, several home-grown special application languages, and the machine code for the IBM 7090, 1410, 705, STRETCH, Dec’s PDP-1 and a few other machines. I had also studied in a bookish way quite a few other machines while doing competitive analyses for IBM.

I was able to help those clients largely because their problems seldom had much to do with the details of their chosen language(s). Instead, they were people problems of all sorts. The problems that did wind up with a language embodiment were usually easy to spot using my general knowledge of computer languages and typical errors people made in using them. That’s why I’ve always insisted that professional developers should know at least a handful of different language.

I think there's an analogy here with the term "mathematical maturity," something we might call "programming maturity." Here's how Wikipedia defines mathematical maturity:

Mathematical maturity is an informal term used by mathematicians to refer to a mixture of mathematical experience and insight that cannot be directly taught. Instead, it comes from repeated exposure to mathematical concepts. It is a gauge of mathematics student's erudition in mathematical structures and methods.

For instance, a mature mathematician is able to transcend notational differences, unlike my tutorial student who flunked algebra because he had learned to "solve for x," but said, "You didn't teach me to solve for y."

We could easily use most of those words to define "programming maturity," the ability that allows you to succeed in a developer job using a language in which you have no previous experience.

The Psychology of Computer Programming: Silver Anniversary Edition