What do you understand "I substituted x for y" to mean?

I went to Burger King the other day and asked if I could substitute onion rings for the fries. The cashier asked, “Do you mean fries for onion rings?” (The meal normally comes with fries). I rephrased it as, “I would like onion rings instead of fries” so there was no misunderstanding. I just thought it was one guy getting confused until I heard somebody else say he substituted x for y where x was the thing he started with and y was the thing he ended up with. I always thought if you say, “I substituted x for y” it means that you started with y and ended up with x. Do I have it backwards? How would you ask for onion rings instead of fries?

Most of the time, this shouldn’t even be ambiguous. The default is fries, onion rings isn’t the standard, so if you hear the words “substitute” and “onion rings”, there should be no confusion.

Same with recipes. “I substituted greek yogurt for the mayo in my potato salad”. Mayo is the standard when it comes to potato salad; the replacement definitely comes after the word “substituted”.

You’re saying it right. Grammatically “substitute x for y” literally means to replace y with x.

I’ve also been hearing people using it backwards. They’re using it as if it’s “substitute x with y”. Unfortunately it seems to be a growing trend.

I have no idea how it started but I find it frustrating because it makes such statements ambiguous.

Huh. Weird. Yeah, the way you said it is fine. I don’t recall ever hearing it in the reverse, but I’ll keep my ears perked up for it now. There’s “substitute X for Y” which means instead of Y, give me X, and “substitute X with Y,” which means, instead of X, give me Y, as davidm writes above, though the former construction is much more usual in my experience.

Substitute x for y - give me x instead of y
Substitute x with y - give me y instead of x

If people are habitually familiar with only one of those forms, I guess they’re a little likely to mishear or misunderstand the other - I imagine it’s also a little worse still for ESL individuals, because prepositions such as ‘for’ don’t always have exact equivalents in other languages

What funny is I read it immediately that x is what you had, I voted that way but the more I think I think it is equally valid to use the other construction and let context explain the rest. It’s fine to say “I’d like to substitute Onion Rings for the fries” in a situation where you have fries and want Onion rings. The person on the other side of the conversation presumably knows what you have vs. what you want.

This is why I always try to say “instead of fries, let me get a quesadilla.”

I can see where it would be confusing, even if your grammar was correct. I might have said “Can I substitute the fries with onion rings?”, in which case “fries” would come first rather than “onion rings.” Though KneadToKnow’s method is clearly superior.

I think “substitute x for y” where x is the thing you want is the correct formation. However, I never trust the cashier at a takeout place to understand that. I always list things I specifically do not want: “I’m going to tell you the things I DO NOT WANT on my sandwich: NO onions, NO peppers, NO mustard. I would also like you to add some cheddar cheese.”

This method still doesn’t always work, but it has a better success rate than anything else I’ve tried. I have just learned to carefully examine my sandwich and all of its ingredients before I leave the restaurant (and dump the onions in the trash as necessary).

Thanks, everyone. It’s good to know I haven’t been saying it wrong this whole time. Encountering two people who thought the reverse was correct within a few days made me wonder.

IMO you have it right.

I think the 2 people you mention are part of a new movement. They use whatever word comes to mind and then hand wave “everybody knows what I mean”.

I think most people became aware of the movement from people ranting about “literally” and “could care less”, but lately other words and phrases are falling to it.:smack::smiley:

I too thought it was ESL substrate interference, but the wise clerks of Oxenford say the controversial construction has been in use since the late 17th century.

I always see the Italian verb sostituire used in that sense of “lose X and get Y.” There have been plenty of Italians emigrating to England since the 17th century, so maybe it’s their fault. Talking about how to make pizzas when only English ingredients are available.

Solid policy generally.

Why don’t you just tell them to put the mustard, onions, and peppers in a separate container?

Then throw THAT away…

I too have heard this more ambiguous, less correct way of phrasing it. I suspect this is done by the same folks who say “do you want to come with?”

This. “Instead of fries, can I have onion rings?” always works.

“Substitute x for y” to get x instead of y.
“Substitute x with y” to get y instead of x (although I find this awkward-sounding, and personally would use “replace x with y”).

I’ve seen a number of people getting these confused, and it frustrates me every time.

Well at Burger King (which I go to fairly often). The right way to say it is
“No onions, add Pickles” They understand that because that’s the way the register order buttons read. Or if there are already pickles and you want more you say “heavy pickles”.

I’m not sure if it works the same way for onion rings in lace of fries, but you could try it.

Funny. This bit of confusion happens every time a bunch of soldiers are sitting around eating MREs. See, once they’ve all opened their bags of food, the trading starts. Some people want cheese instead of peanut butter. Some people want M&Ms instead of pound cake, etc. Without fail, at least once per meal, this pit of x for y confusion will happen. And it is worse, because unlike the OP example, there is no default. Inevitably, someone will say, “Who will trade cheese for peanut butter!?”
Someone shouts, “I will!” and throws him some cheese, hoping for peanut butter to be thrown back.
Instead he gets, “No!! I have cheese. I want peanut butter for it!!”
Every. Damn. Time.
You’d think we’d figure out language by now.

Maybe the cashier was just checking because he couldn’t believe that anyone actually wanted the onion rings.