By Rabbi Yair Hoffman
For those who deal with beginners who are just coming back to Judaism: There is a fascinating Mishna Brurah (593:2) and Biur Halacha (Zu). In these two works, the Chofetz Chaim states that if a person is only familiar with one blessing in the Shmoneh Esreh, he should still recite it and he can fulfill his Torah obligation of praying. He should, however, connect it to another blessing right beforehand.
This position is the final conclusion of the Chofetz Chaim, but it is controversial. The Mogain Avrohom, Eliahu Rabbah and Rav Ovadiah Yosef all disagree. They attempt to prove this from the halacha that one who leaves out one blessing in Shmoneh Esreh does not fulfill the Mitzvah (OC 119). Thus Sefardim should not follow this Mishna Brurah.
How would the Mishna Brurah deal with the Halacha in 119? He would have to say that the sages did not ordain that law in a dire situation when there was no other choice. What then might the other Poskim hold about this distinction? They would perhaps hold that the sages did not wish to have so many categories so they made the halacha of 119 across the board.
The same debate is true regarding someone that does not have a siddur in hand and is in a place where one is unavailable. According to the Mishna Brurah, he should recite the blessings that he remembers. According to others he should repeat the Shmoneh Esreh twice at Mincha when a siddur is available.
Rabbi Hoffman can be reached at email@example.com