The article is painful to read. For one thing, the author comingles the GUI terminal app with the shell, which are distinct things.

A GUI terminal doesn't need to run a shell, even if often it does.

e.g. "xterm -e emacs", now the GUI terminal is running emacs, not any shell.

(Of course arguably emacs is a shell and a universe onto itself but different topic.)

And a shell is called a "shell", not a "shell language". Yes a shell can be used as a scripting language, but when used interactively it is called a shell.