The mitzvah of tzitzis is a chovas gavra (an obligation on the person who wears a four-cornered garment) and not a chovas mana (an obligation that applies to the garment itself). This means that a person is only obligated to attach tzitzis to a garment that he is wearing, not to one that he merely owns. A person who wears multiple four-cornered garments must affix tzitzis to each of them. If he will be putting them on consecutively, he should recite one brocha to cover all the garments. Since the brocha is being recited for all of them, it is forbidden to talk from the time that the brocha is made until they are all put on. The poskim disagree about whether a person must make another brocha if he did speak. In such a case, he should delay putting on the additional articles of clothing until a considerable amount of time has passed. At that point, he can recite a brocha according to all views.
[שו"ע ח, יב, ומשנ"ב כז ו־כח; ביאורים ומוספים דרשו, 35 ,39 ו־41]