From it I learned a remarkable nugget of computing history: P.J. Plauger, well known as a C language guy (he and I were both on X3J11, the C Language Standards committee), originated the idea of using significant white space as the "signal" to the compiler to indicate statement grouping instead of using begin/end keywords or braces.

On the other hand, it had explicit syntax sugar that was specific to the HyperCard environment (thus actions like `ask` and `answer` for simple modal dialog prompts), along with phrasing intended to make things read in English and even avoiding basic operators (thus, `put ... into ...` as an assignment syntax, `the number of` as a length operator, `it` referring to the result of the previous line in some contexts, ...). And of course, the HyperCard environment was event-driven; you could write explicitly callable functions, but your entry point was only ever some GUI interaction, not top-level code or a "main" function.

Perhaps you could say that they both came from a similar philosophy about how to make a programming language "natural-language-like". Which IMO was a big step up from COBOL at least ;)

Installable under current OSes? Looks like a yes. Assuming your OS still provide 32-bit compatibility mode.