Stop Worrying Start Coding

I agree with the conclusion - stop worrying, start coding; but not with the arguments. Code is a form of communication; Communication has speed. Communication speed is related to things like redundancy and vocabulary.

A language with a lot of redundancy, like English or Java, is slower than one with generally less reduandancy, like Japanese or Python. Redundancy can be within syntax (like long words), or with context (like implied subjects in Japanese, writing "self" in Python, or declaring types in Java) - redundancy protects against signal/context loss, but its cost is in speed.

Vocabulary represents an abstraction of a concept. A person with a smaller vocabulary in a particular topic will take longer to express a concept than one with a large vocabulary in that area. If a language has a small vocabulary in a particular area, it will be slower than a better suited language.

In the end, getting the message across is more important than the speed of getting it there, but if you have a choice, use only as much redundancy as you need to get the signal across, and choose the language which gives you the largest domain specific vocabulary.

I disagree about choosing a language. I've been bitten first-hand when choosing a language for something it isn't good at.

These situations are pretty few and far between, but they do exist. I once used VB for a very processor-intensive algorithm because it was the best tool I had at the time for GUIs. For easy problems, the tool worked fine. It was about a week until I hit a problem that took hours to run on it. A few days later, I hit a problem that took days to run.

Had I written it in a more suited language, I could have delayed that problem... Possibly forever.

I actually consider rewriting that code even to this day... But I don't really have a good use for it now, like I did then.

In short: For that problem, I followed the advice in this post, and I was burned.

The general advice here is very good, but the point of languages being fast or not is in fact discussible.

Languages with cleaner semantics ... are faster to code.

Languages that are easier to implement ... have more fast implementations.

Languages that have more fast implementations ... are likely to have one very fast implementation.

HOWEVER! Worrying about all of this before you've coded anything is premature optimization. Before you're holding something that is too slow in your hands, the only speed that matters is how comfortable you are with a language and how quickly you can code with it.