Can the parshios of Shema be said out of order?

The words of each parsha of Kriyas Shema must be said in the order that they are written in the Torah. The pesukim must also be read in order. If the words and pesukim were said out of order, one is not yotzei and he must repeat Kriyas Shema. L’chatchilah, the parshios of Kriyas Shema must be recited in order as well. B’dieved, though, one is yotzei even if the parshios were said out of order. If one reads a later pasuk before an earlier pasuk, he only needs to repeat the later pasuk. The reading of the earlier pasuk is acceptable if the later pasuk is read afterwards.

סעיף א, ס"ק א-ב, וביה"ל ד"ה במה וד"ה אף

What must be repeated if a word was omitted?

A person who either skipped or mispronounced a word must go back to place where the error was made, correct it, and continue with the rest of the parsha. If the word that he omitted was in the middle of a concept, some say that he must go back to the beginning of the pasuk. One who became distracted and lost his place must go back to the beginning of the parsha. If he is not even aware of which parsha he was up to, he must go back to the first parsha.

סעיף ב וס"ק ה-ו; ביאורים ומוספים דרשו, 2

Which pasuk is found in both parshios?

The pasuk of U’chsovtam is found in both the first and second parshios of Kriyas Shema. If a person was saying this pasuk and forgot which parsha he was up to, he must go back to where it is written the first time. If, however, he continued with lema’an yirbu, it can be assumed that he is in the second parsha. If one lost his place when reading along with a group of people, he should rejoin the tzibur regardless of which pesukim he found himself saying.

סעיף ד וס"ק י-יא; ביאורים ומוספים דרשו, 6

• A person must have a proper understanding of the words and ideas in the first pasuk of Kriyas Shema and Boruch Shem. This halacha is separate from the general concept that mitzvos require intent (to be yotzei the mitzvah).

• It is forbidden to talk during all three parshios of Shema. During the first parsha it is also forbidden to signal or motion, even for the sake of a mitzvah.

• There are three opinions regarding which sections of Kriyas Shema are mid’orasia and which are only mid’rabonon: 1) only the first pasuk is min haTorah, 2) the entire first parsha is min haTorah, and 3) the second parsha is also min haTorah. 

• Why do the Kohanim sing in the middle of Birchas Kohanim?

• If one took a break in the middle of Shema, does he have to repeat it?

• If a person interrupted his Shemoneh Esrei due to a hold-up, should he say it again?