If you don’t like off-color jokes, skip down to the next paragraph. But there is an old joke that has been floating around Boston for at least a half century about a woman who grabs a cab at the airport and asks to go to downtown Boston. On the way she effusively talks about all the things she wants to do and see on her first trip to that city. Halfway into the city, the driver asks her where she would like to be dropped off. “Anywhere I can get scrod!” she exclaims with glee, thinking of the popular New England fish. “Wow,” replied the driver, obviously not a fish-eater, “That’s the first time I’ve ever heard the subjunctive pluperfect of that verb.”
I still hear people of my generation say things like, “If Harry were more careful,” and “Were mom to hear what you just said . . . .” Most speakers still seem to still prefer, “If I were you,” but that is probably a crystallized idiom now. “If I was you” does occur, though, so Somerset Maugham was probably right when he said, “The subjunctive mood is in its death throes, and the best thing to do is to put it out of its misery as soon as possible.”
In fact, the subjunctive mood is still around; what has changed is the use of the plural past tense to mark it: “If I were,” “If he were”. “If I was you” means the same thing as “If I were you”. Was here still implies a conditional, nonexistent or impossible situation rather than serving its usual function, the past tense. What has happened is that the past tense endings are now being uses without any modification to indicate the subjunction mood. “If I was you” is different from “If I am you” in exactly the same way that “If I were you” is different from “If I am you”. Was clearly is not indicating the past tense in these phrases.
The problem is one that I think I’ve written about before: English is losing its affixes for a reason linguists have not been able to establish. However, it is not losing the functions (meanings) of those affixes; rather, more and more functions are expressed by any given affix. Look at all the functions -ing has: I’m walking the dog (verb), Walking seems to be a popular sport around here (noun), The walking dog is dangerous (Adjective), Walking the dog, I happened to see Renfrow (Adverb)—without even thinking about words like roofing, flooring, siding that are derived from nouns.
So, what is right, “If I were” or “If I was”? Whenever language enters a state of change like this, speakers don’t change. There is no reason for anyone to change their speech. If you are comfortable with “If I were”, continue using it but keep in mind that the younger generation will be using “If I was”.. If you think it sounds old fashioned, say “If I was” but remember that “If I were” is still acceptable until those of us still using the subjunctive are in our death throes. Until then, we are all speaking the language as we learned it perfectly grammatically. (I would like to thank Kathleen McCune of Norway for asking.)