My friend is trying to convince me that the following statement is correct when talking to a group of people.
To me, the following sentence seems correct rather than the former because every individual in the group only has one right foot.
I'd love to know which of these is correct, or if they are both are right then why (or why not).
You are right. And to use "feet" sounds absurd, as if a centipede were advancing multiple right legs simultaneously.
Marjorie Skillin, Words into Type (1974): "To avoid ambiguity, a singular noun is often used with a plural possessive when only one of the things possessed [or in this case one pair of legs] could belong to each individual" (p. 357). Among the examples given are these:
Forbes knew most of them by their first name.
They eyed each other furtively and cursed under their breath.
If text surrounding your sentence makes it clear that a group is addressed, then the reader will know that "you" is in the plural; otherwise one could not tell whether "you" is sing. or pl. when the singular "foot" is used. Or the sentence could say, "You all need to put your right foot in front of your left." (That's not meant to evoke you-all as in Southern dialect, but simply means "all of you.")
It doesn’t matter how many of “you” there are. You each only have one right “foot” so the singular is the only correct statement here.
Whether you addresses an individual or a group, “your right feet” is nonsense because none of you have multiple right feet (assuming you’re all bipedal).
"You each need to put your right foot in front of your left" is how I'd use the singular and be precise/technical about it.
But assuming the suggestion is literal - e.g. it's coming from a dance instructor - then I don't think there's anything grammatically wrong with 'you all' + referring to the entire group's right feet all at once.
(And that would still include the assumption that no smart-ass in the group is likely to respond with "So I can put my right foot in front of someone else's left?" or "Okay, why don't we get in a circle, each grab our neighbor's right foot and place it in front of their left?")
Even if the context is the figure of speech, all of the above (other than the smart-ass semantics) still apply, but as the whole thing is non-literal, less formal etc. it's a bit more academic/trivial.
