Replace a deictic second-person pronoun `you` with one of the two number-marked forms when recipient cardinality is load-bearing. `you-one` denotes exactly one addressee. That individual must already be uniquely recoverable from the communication envelope, a name or mention, or another explicit addressing cue. `you-all` denotes exactly every member of an explicitly established addressed group, and that group must contain at least two members.

The forms occupy the ordinary subject or object position of `you`: `you-one must sign the receipt`; `I sent the receipt to you-one`; `you-all may inspect the archive`; `the warning applies to you-all`. They retain ordinary second-person agreement and case behaviour; this filing does not create possessive or reflexive forms. Lossless round-trips: `you-one must acknowledge` ⇄ “the one addressee denoted by this clause must acknowledge”; `you-all must acknowledge` ⇄ “every member of the addressed group must acknowledge.”

The markers declare the size and boundary of the second-person referent, not how many action instances occur. `you-all will inspect the archive` can still mean one joint inspection or one inspection per member; compose `as-one` or `each-alone` when that distinction matters. `you-one` does not mean “you alone are responsible” and does not exclude another independently addressed actor from having the same duty. The forms do not establish authority, delegation, delivery, receipt, identity, or whether a request is binding; those axes remain separate.

SCOPE: only deictic address is served. Generic `you` (“you never know”), quoted or force-suspended text, and a reference whose addressee set cannot be recovered are out of scope. In a group thread, `you-one` is invalid unless the one intended recipient is separately resolved; it must not select a member by guesswork. `you-all` refers to the addressed group at the utterance, not every later reader after forwarding or publication. Bare `you` remains legal and number-unspecified. Hyphen loss yields `you all`, which preserves the plural reading, and `you one`, which is awkward but keeps the intended number visible rather than flipping it.
{"you-all":"the deictic second-person expression denotes every member of the explicitly established addressed group, whose size is at least two","you-one":"the deictic second-person expression denotes exactly one addressee, uniquely recoverable from the message context"}