Would you consider binary lambda calculus [1] [2] a real language?
The 650 byte interpreter written in obfuscated C also sports garbage collection and might fit in a bootsector when translated to x86 code.
Its metacircular interpreter is only 29 bytes (232 bits),
and looks somewhat readable with some syntactic sugar [4]
(analogous to how x86 looks more readable as assembler source).
[1] https://www.ioccc.org/2012/tromp/hint.html