Small and Fast
jimbokun.github.com
jimbokun.github.com
Those affect the design of the language. The simplicity of the interpreter/compiler is also very important to build a community of code dev.
A PL is an ecosystem, the implementation is the core but there are so many other important things...
Agreed that simplicity is an underrated feature of programming languages (Rich Hickey had some very interesting things to say about this). That's kind of hinted at in my article with Yaron Minsky praising the consistency of OCaml performance, compared to the difficulty people have predicting Haskell performance.
And agreed that the most important aspect of a programming language is the quality of the culture built around it. I wonder, do the characteristics of the language determine the culture, or are they largely orthogonal?