Why can't we say "This meat is for Pesach"?

Question

For the 30 days before Pesach, we are not supposed to say "this is for Pesach," but rather "this is for Yom Tov." The source indicates that the prohibition applies especially to utterances regarding meat, i.e., "This meat is for Pesach."

What is the reason for this prohibition? Is it because it could be understood as a false declaration that the meat (or other stuff) is the real korban Pesach?

Also:

-What are the legal origins of this prohibition, and what level of force does it have? (Is it halacha, minhag, or just superstition? Whose minhag/superstition, and from where/since when?)

-Does the prohibition apply only to that exact expression ("this is for Pesach")--or to what types of expressions in general?

Answer 1

It's from the Talmud (Pesachim 53b) with the reason given as "for it looks like he is consecrating his animal and consuming an offering outside [of the Temple]". The Shulchan Arukh codifies it as well (OC 469). (The Arukh haShulchan (ibid. :4) notes that the Rambam did not codify this rule, and thinks that he omitted it because he thought it only was true according to one opinion in the Talmud (that we don't rule like) that to consecrate an animal as an offering it need not be done "in the manner of those whose volunteer offerings".)

In terms of the language, the Magen Avraham there (sk 2) notes that saying בשר זה על פסח instead of לפסח is not a problem. I don't know enough about his dialect to know for sure how to translate those phrases precisely, but it seems that the expression needs to be clear and accurate enough to have actually served as a statement of consecration.