Maple
Maple is a high-level programming language used for mathematical computations, symbolic computation, and creating interactive educational tools. It is widely used in fields such as engineering, physics, mathematics, and scientific research.
Hello, world code example:
> printf( "Hello world!\n" ): # print without quotes
Hello world!
Popularity: Less than 1% of developers are using or have used this language.*
*According to StackOverflow's 2023 survey.