If you want to see the available kernels for each language you can check it here: https://github.com/jupyter/jupyter/wiki/Jupyter-kernels
Originally the whole project was ‘IPython’ and then ‘IPython Notebook’. It came out of Fernando Perez’s attempt to make interactive Python a better experience.
They renamed it Jupyter to reflect that it was no longer a pure Python project as kernels were written in even before it rebranded as Jupyter. Those three were the most popular at the time but by no means the only ones.
I used to work with one of the core team about the time they changed this!
TIL!