Google has a bunch of internal languages that are only used within it, don't enjoy a wider adoption, and get deprecated.
Facebook created Hack, a version of PHP with a quite nice static type system, which is virtually not used outside it. They also had an early statically typed version of JavaScript, called Flow, which enjoyed a limited success, but was supplanted by Typescript.
Haskell, OCaml, Erlang, Smalltalk, etc all enjoyed some success in specific narrow domains, while influencing heavily such mainstream languages as Python, Java, Typescript, Rust, and, well, Go.
Compared to this, Go is unreasonably, blindingly successful; it's now all over the place, but that was hard to predict back in the early days of the project.
Facebook created Hack, a version of PHP with a quite nice static type system, which is virtually not used outside it. They also had an early statically typed version of JavaScript, called Flow, which enjoyed a limited success, but was supplanted by Typescript.
Haskell, OCaml, Erlang, Smalltalk, etc all enjoyed some success in specific narrow domains, while influencing heavily such mainstream languages as Python, Java, Typescript, Rust, and, well, Go.
Compared to this, Go is unreasonably, blindingly successful; it's now all over the place, but that was hard to predict back in the early days of the project.