c_corgi, on 2012-August-09, 09:12, said:
It is clear that declarer's intended designation was dummy's lowest spade, so the change is allowed.
Unfortunately you have made the common confusion between the colloquial interpretation of the words "intended" and "unintended" and the legal definition of "unintended designation". It is just like the situation where you quite clearly "intend" to show 2 Aces in response to Blackwood, but by miscalculation you bid 5D instead of 5H. That was not a mispull, it was a miscalculation. It was precisely the bid you intended to make at the time you made it. The fact taht it didn't achieve your deeper intention of communicating "2 Aces" was due to miscalculation, not unintended designation. I hope it is clear to you that the law does not let you change it when you realise you have miscalculated, because this is just the same situation here.
There is no doubt that when declarer uttered the word "two", that is the word he intended to utter. Thus, legally, it was not an unintended designation. Indeed it was precisely the designation he intended to make. What went wrong was his calculation of what that (incomplete) designation would achieve. The fact that it did not achieve that outcome was because he made a miscalculation about what (incomplete) designation would achieve that outcome, based upon his faulty observation of which spots were on table. Such miscalculations may not be repaired under the unintended designation law.
Further, his designation was incomplete. But it was entirely his intention to make such an incomplete designation and live with the consequences of it. So he cannot cancel the designation it on the grounds he hadn't completed it yet, and start again, as he had never intended to say any more, it was completed as far as he was concerned. If he had not thought to calculate what incomplete designations might achieve the outcome he hoped for, and made that incomplete designation, he would not have been at risk of miscalculating.
And if on another occasion he says "low trump", and dummy picks up the 2 from where it was mis-sorted above the 7, and declarer says "actually I wanted the one at the bottom, the 7, obviously I didn't want to under-ruff", I won't let him get away with that change either.