They taught me Pascal in the early 80s, and since I don't want to invest much time to learning the quirks of other languages, it has become a kinda native language for me. Alas, I was forced to migrate from the Borland dialect to FreePascal and/or Delphi with the discontinuation of DOS :-)
My CAS of choice has been Mathematica. Not out of love, but for reasons of availability. It actually is not too bad, once you get used to its idiosyncracies. Earlier I did stuff with Maple for similar reasons.
When I worked in the industry side for a while I had to use ANSI C and Matlab. I will never voluntarily use either again. Too difficult to remember the syntax for file/screen I/O functions or the pointer logic in C, and Matlab is A) outrageously priced, B) for numerical stuff only (but has that excellent support for telecommunications applications, which fitted my former employee employer nicely).