Named after a snake? Not one of them
PYTHON has nothing to do with the reptile. Guido van Rossum was reading the scripts of Monty Python's Flying Circus while he built it, and the official documentation still hides sketch references in its examples. JAVA began life as Oak, named after a tree outside its designer's window, and was renamed in 1995 after the coffee — which is why its logo steams.
LUA is Portuguese for moon, chosen at a Brazilian university because the language it grew out of had been called Sol, the sun. PERL was going to be Pearl, after the pearl of great price, until its creator found the name taken and simply removed a letter. And RUBY was named as the jewel that comes after PERL — a small joke that has now outlasted most of the software written in either.
Named after people, or nothing at all
Another group carries somebody's surname. PASCAL honours Blaise Pascal, who built a working mechanical calculator in 1642 while helping his father with tax accounts. HASKELL is named for the logician Haskell Curry. ERLANG does double duty: it nods to a Danish mathematician and to Ericsson, the phone company that built it to run telephone exchanges that were never allowed to stop.
The oldest names are just descriptions with the vowels knocked out. FORTRAN is formula translation. COBOL is common business-oriented language. BASIC is a beginner's all-purpose symbolic instruction code, invented at Dartmouth in 1964 so that students who were not scientists could use the college computer. ASSEMBLY is the odd one out — barely a language at all, just human-readable labels for the instructions a processor already understands.
Why anyone needs more than one
It looks wasteful until you notice that each was built for a particular job. SWIFT exists because Apple wanted a safer language for iPhone apps, and KOTLIN plays the same role for Android. MATLAB and JULIA are built around the way mathematicians actually write equations. RUST was designed to make a whole family of memory bugs impossible rather than merely discouraged. TYPESCRIPT exists to add a safety net to JavaScript without abandoning it.
Others chase a style of thinking rather than a platform. HASKELL, CLOJURE and SCALA lean on functional programming, where you describe what you want instead of the steps to get it. DART, GROOVY and LUA each found a niche — apps, build scripts, and being small enough to embed inside a game engine. The choice of language is really a choice about which mistakes you would rather find impossible.
The old ones never left
Programming languages rarely die; they retire quietly into places nobody looks. FORTRAN, first released in 1957, is still running weather and climate models, because decades of carefully checked physics code is not something anyone rewrites for fun. COBOL, from 1959, still moves an enormous share of the world's bank transfers and payroll, and banks periodically discover that the people who understand it are retiring faster than they can be replaced.
That is a useful thing to know about software: the flashy language of the moment is rarely the one holding up the plumbing. Whichever of these a coder picks, the machine ends up executing the same ones and zeros — the language is a convenience for the human, not the computer.