This is only guesswork. I think Dahl is trying to get down with the kids by attempting text talk. Esl I assume is English as a second language, we don't call it that we call it Efl, English as a foreign language, because there are those who can speak more than two languages.
Pol I guess is politics, but it could be polygamy, Phil, may be philosophy, but it could be the Philippines, the works of Philip Roth, or just some some guy called Phil Dahl met on holiday. (He is over 80 you know.) Rel, perhaps means religion, but it could be relative butt sizes, Dahl has never been the same since he saw that picture of Kim Kardashian shitting in a bin liner.