Swift, Go are somewhat obvious names for a programming language (they express speed and action), and if you keep in mind *every smaller languages, it's almost impossible to come up with a name that nobody used as a programming language.
Sure, don't start a new programming language and call it Python or Java, but how about Falcon, Cheetah, Quick, etc? I never heard about any of them, but I'm sure there exist somewhere a programming language written by a solo developer that uses one of these names.
Falcon was also a computer system from Atari. Cheetah is also at least a computer system, a brand of drive, and a template system for Python. I don't know of languages called Cheetah or Quick. They may exist. "Quick" was part of the name for multiple programmers' tools and language implementations from Microsoft - QuickBasic, QuickC, QuickPascal, QuickAssembler... maybe more. They competed with the Borland Turbo C, Turbo Pascal, Turbo Assembler, Turbo Prolog, and Turbo Basic languages. This was back before MS switched to Visual C++, VisualBasic, etc.