New Languages Considered Harmful: "Learning new languages is a waste of time."

Aside from the immediate reasons, there's some merit to the mind expansion argument. I think being proficient in at least two languages is indeed important for boosting your ability as a developer. This resembles human language: learning a second one changes the way you think and your perception of the world. The third or fourth, not as much. But it can't be any two languages. If you know Portuguese and Spanish, your mind didn't have to expand much. Likewise, learning VB.net and C# doesn't count.

I think "enough" is a crucial point here. The author almost seemed to be arguing against switching to a new language every year, which I agree is ridiculous. The idea is to learn some new concepts, not to write significant programs in a new language every year. I only adopt new languages for regular work if they're the pragmatic choice.

I'd also suggest that of the two pathological conditions -- Overdabbling and Underdabbling -- the Underdabblers outnumber the Overdabblers by a huge margin. We just see a lot more of the latter on the Internet, because for many obsessive dabblers the whole point is to brag about it.

You need to find a balance. In the end, I think this essay is much more about that balance than its title suggests.

Q: What computer do you have at home

A: I have five.

Q: What OS do they run?

A: All of them. ;-)

As someone who is starting to step out of the comfort zone of Java, I agree about marketability. However, Java is not going to disappear, it's firmly entrenched. It's like COBOL. I'm not sure how Sun pulled it off exactly but Java in it's 13 years has spread itself in a lot of corporate systems/applications/backends (some of which may be COBOL). Ruby on Rails and other minority languages are the minority in some companies precisely because the majority don't like the minority ("RoR? We don't use that"). However, there are some rogues in companies who are trying to bring RoR in discretely (I'm trying to be one - developing business cases for RoR adoption on small projects)

This is a good point. It is probably not a good use of your time to learn Java and then C# (or similar), or Perl and then Python and Ruby. Sure, there are differences, but basically the languages in the same groups are the same.

If you go for the more "academic" languages, you'll get more return on your learning investment. Recently, I've learned Lisp (this is what started me down the "wait, learning new languages isn't a waste of time!" path), Smalltalk, and OCaml, and I've picked up a lot of good ideas to port to my primary language. (Otherwise, my background before that was C, Perl, and Haskell. All good languages to know :)

But even in your situation, I'd say balance languages with other knowledge that is important. It's easy to play with languages because it's fun, but there's a lot of other important stuff to learn, some of which might make more practical difference to you.

But by all means, learn and have fun. If you're getting a kick out of languages, have at it, especially if you've got plenty of time.

<sarcasm>

So would gargling Drano.

</sarcasm>

(I always thought about COBOL like this: Let's spend 3 hours getting dressed to go outside and pick up the mail.)

"Doing this is like doing a really bad thing, which by the way you shouldn't do."

One of the things the guy missed is there in plain sight in his essay:

You need to get to know the libraries, struggle with the environment, find or tune a text editor, look for tools, and so on. Most of the effort has to do with housekeeping chores, which are surely not mind-expanding by anyone's measure. If you hope to be productive in the new language, things are even bleaker: proficiency has less to do with the language itself than with the myriad technologies you must master to use it effectively.

Unfortunately, everyday productivity is a lot of housekeeping chores, one after another. While your higher mind is soaring with the architecture astronauts, the rest of your mind had better be editing text efficiently, and running top and netstat, and administering the version control system.

And more than half of the point of learning a new language is to force yourself to experiment with a different tool ecosystem. The point of learning Ruby isn't just to learn Ruby: You get to learn about Rails and Capistrano and the obsessive use of test-driven development and, in my case, git. (If I'd been a kernel hacker, I'd have known about git. I presume the Rails folks learned about git because some kernel hackers, seeking to learn a new language, wandered into the Rails community.) You want to be forced to experiment with different tools because sometimes they're better: git is just a much better tool than Subversion, and don't get me started on CVS. Even when the alternatives aren't better, you become a better technologist by playing with them. If I'd never played with a Java IDE I would have no chance of understanding how Java programmers think. If I'd never actually deployed both Rails and PHP I wouldn't understand why PHP deserved to live. (Yes, it's filled with stupidly broken parts, but it's so easy to deploy, and it's fast, and it's not that hard to comprehend.)

The other thing this guy doesn't seem to understand is that there's a difference between tourism and living in another country. When you "learn a new language every year" that doesn't mean you have to become a pro in your new language. You can visit, kick the tires, read a couple of introductory books, write some simple code, read some code to something more complicated, and then move on. Yes, that means you're a dilettante -- but it's better to be a dilettante than to blindly plug away at the same thing for a decade.

A web-style APL should let you do something like that as tersely as APL lets you compose operations like +.×/ for the inner product.