Apple - Do Macs come with any programming language available from the Terminal?

You have good old bash (or csh, or whatever). You can use it to write shell scripts.

Terminal runs the Unix shell, (bash, zsh, and others) which is obviously a command line scripting environment, which can execute complex scripts, particularly file processing.

Python 2.7 comes bundled with MacOS, and always has done. Future?.

Ruby, Perl are also included.

AppleScript and its JavaScript equivalent (docs) are also there out-of-the box.

I'm on Mojave and Python, Ruby, and Perl are installed by default. But I understand that there is a Deprecation notice with Catalina that says future versions of macOS won't include scripting languages by default.

As suggested, as a clarification there are Unix shells in macOS, although in Catalina the default shell is zsh.

Testing on a 10.5.8, El Capitan and a Mojave computer - perl, ruby and python responded on the command line without providing any paths. Perl and ruby are in /usr/bin/ on each machine.