I make an exception for variables with short names: “dollar underscore”.

I pronounce everything if I am reciting a perl script over the phone. (Don’t laugh, this happened to me last summer. I went on holiday without net access, a server died in my absence, my colleagues needed guidance on how to make the spare server work, in lieu of remembering how to use the find command I wrote a perl script. With pen and paper and lines I numbered myself.)