What was the first programming language that had user-accessibility? For instance, a programming language that offered itself to the public for experimentation, personal use, hobby, etc; something that wasn't just 'behind the scenes' and for use by big companies for putting together professional products and services.
BASIC (1964) was at the very least the first popular hobby language.
It may not have been the first available but one of the most important has to be Integer BASIC, known as Apple BASIC originally. It was included with the Apple II.
I spent a lot of time in Commodore BASIC on my home Commodore 64 (a version of Microsoft 6502 BASIC very similar to Apple BASIC) and the various Apple computers my school had. Part of the reason I'm a programmer today is the joy of seeing the teachers struggle to exit an endless loop, finally giving up and rebooting the computer so the next kid could play Joust.
If you count initial conception and prototyping, I'd give the vote to Forth.
The Micral is regarded as the first personal computer. I believe you could only write programs for it in 8008 machine or assembly language. As for hobby languages (which were used on hobby computers), machine languages were the first, usually entered via front-panel toggles. The SCELBI and Mark-8 were the first marketed hobby computers; before that, hobby computers were custom made by their users, with instruction sets often cribbed from the PDP-8 instruction set[2]. The first higher level language was the version of BASIC produced by Bill Gates and Paul Allen for the Altair[3].
Further references:
- The Micral, Armand Van Dormael
- The early days of personal computers, Stephen B. Gray
- Short History of the Microcomputer
- Wikipedia: Micral
- Wikipedia: SCELBI