Too many languages

There are thousands of programming languages.

The purpose of a programming language is to express programs. The
purpose of learning programming languages is to build up a toolbox for
reasoning about and synthesizing programs in any one given language.

There are diminishing returns on learning programming languages, and
time is scarce.

Therefore one must select between programming languages to study.

A good selection of languages has both
+ breadth
  + satisfies a number of real world economic needs.
+ focus
  + exploits similarity between languages and incremental learning.
  + some unifying basis

A good member of a particular selection meets a number of the
following criteria:
+ Satisfies one particular school of thought on programming languages.
+ Significant difference from predecessors
+ Significant influence on successors
+ Economically significant
+ Advanced i.e. no direct, established and proven heir.
+ A good language.
  + Easy to express programs with
  + Easy to read programs expressed with
  + Easy to reason about programms expressed with

No one of these criteria are sufficient or even necessary conditions.

A bad member satisfies the opposite criteria.

>>36
von neumann machines would be a research topic with both academical and commercial interest
*hypothetical world where FPGAs and dataflow architectures are the norm and von Neumann means some embedded 8-bit chip*
Mainstream computers are doing too many computations at once. I mean, who wants to be able to calculate the length of an arbitrary linked list in one cycle per element while doing a bunch of other stuff at the same time? Who wants to be able to add multi-dimensional arrays in one cycle? We should force programmers to load everything through a ``cache hierarchy'' into these things called ``registers'' and come up with gimmicks called ``out-of-order execution'' and ``register renaming'' so we can have our CPU do 3 or 4 things at once but pretend it still does only one thing at a time. What took one cycle now takes hundreds! Everything has to go through a tiny path called a ``bus'' about 128 bits or so. I can see commercial prospects too. Those companies would pay us billions to have software that runs 1000x slower, maybe 10000x. So, who's with me?