I think you're generally right. There are exceptions, but in many domains there are standard notations for often-encountered quantities. You say "F" for force

I think you're generally right. There are exceptions, but in many domains there are standard notations for often-encountered quantities. You say "F" for forces, "p" for probabilities, "x" for machine learning inputs, "y" for classes, etc. In some cases, you might want to use English terms for these things, but usually you'd want to use the standard letters. Especially if the source paper that you're following uses some flavor of standard notation. (So many standard notations to chose from!) Of course, coming up with universal rules for naming things is impossible. The advice would probably have been better left out.