[tivert]

>> The learning curve is minimal since you already know the corners of the language.

> Learning a new language shouldn't be difficult. Programmers are expected to familiarize themselves with new tech.

But in practice, it is. Maybe you're on a team of elite 10x programmers that can quickly become experts in anything, but that's rare. A lot of programmers don't want to bother coming up to speed with the quirky choice of some past developer. And a lot of places have programmers that aren't even that good with the "project main language," and just lack lack the ability become productive in that quirky choice in a reasonable amount of time.

Defensive coding against organizational problems is not a bad thing.

[remus]

> But in practice, it is.

Indeed. There's also 'learning' and learning: really knowing all the nooks and crannies of a language, learning the standard library and learning popular third party libraries all takes time and makes a big difference to code quality.

[steve_gh]

Depends on the language. I am competent in half a dozen languages, and write a lot of functional code.

I have written a few projects in Haskell, but I freely admit theat when I read any of Simon Peyton-Jones papers (eg the one on build systems referenced on HN recently) I am in awe of the way he can map concepts into Haskell code.

[lelanthran]

> But in practice, it is. Maybe you're on a team of elite 10x programmers that can quickly become experts in anything, but that's rare.

Pray that you aren't, because that is a recipe for misery.