> Programming languages, like all languages, exist for communication between humans.

That is manifestly false. Machine language and Brainfuck are both programming languages, and they are not designed for communication between humans. To the contrary, Brainfuck is deliberately designed to confuse humans.

Programming languages exist to describe processes with sufficient precision that they may be carried out by a machine. You might want a programming language to also serve the secondary purpose of communicating something to a human that reads it, but the vast majority of extant languages are not designed with this goal in mind.

> The power of modern languages come from us quickly being able to understand programs.

Again, no. The power of modern languages comes from providing higher-level abstractions that are closer to human thought processes. Modern programming languages allow you to think directly in terms of things like numbers, arrays, strings, etc. rather than forcing you to think of everything in terms of raw bits. There are many languages that are notorious for making code much easier to write than to read.

> The vast majority of bugs don't come from under-specification, but rather poor/miscommunication.

No, the vast majority of bugs come from a mismatch between the code and the programmer's mental model of what the code does, i.e. the process that the code describes. You can have bugs in code written by a single human. There is no possibility of miscommunication because there is no communication. There is just the code and the programmer's brain.