The most obvious case being garbage collection, but even strong typing + type inference seems to be going through that with things like Typescript, Type annotations + python type-checkers, Sorbet (Ruby), Concepts in C++, Rust, Dart etc

Dont remember if it was on FoC podcast or some other where somebody complained how unfriendly

git rebase -i

is, compared to some hypothetical direct-manipulation UI, and i thought to myself "what do you mean, rebase -i is direct manipulation on the conceptual level I care for".

On languages, it may depend on how narrowly you define "language design". Some examples where I see large variances in: • Support for introspection & live coding. • how much the language lends itself to internal DSLs. • Crisp vs. fuzzy definition of language: can YOU tweak C++ syntax/semantics in your particular project? Well #define but nowhere near as much as FORTH or Racket ... • Community & inclusivity around language evolution. ◦ Python-ideas & PEP process is, to this day, more accessible that the C standard committee [I see why "C is done" and evolution is pretty much a non-goal, not judging just pointing out difference]. ◦ GHC goal to be "research compiler platform" by definition wanting to accept experimental extensions is a curious example. ◦ (As Don & João said, every early-stage language feels different in this aspect from large long-lived ones, but there are elements of "community design") • Presequisite knowledge. Some languages require you to learn manual memory management, or some category theory, etc... There are pros & cons, but surely a user automating their email flow should not need either of them :-) If you see End-user programming as "the great unsolved problem of computer science", then language design has real simplifying power. • Run-time interoperability with other languages.

(The observant reader will notice all the above axes can be brute-forced by professional tech-giant teams. If you view say maintaining your own compiler+debugger+IDE as "simple matter of budgetting", than all languages become more similar 😎 )

Hmm, there is also a middle ground, where almost anybody will build some preprocessor/generator/linter around a language they dont "control". That option reduces how much "original design" matters. Some designers actually shoot for that as the escape hatch from day one. Still, some choices make that harder/easier. Those can be syntax choices (part of "language design" by all definitions) but also implementation/ecosystem choices like having the official AST [un]parser in stdlib or easily consumable open source... I view the latter as part of my stretched definition of language design.