A person should hear the reading of Parashat Zachor on the Shabbat before Purim from a person who reads according to his tradition. Meaning, a Sepharadi should hear Parashat Zachor read by a Sepharadi, and an Ashkenazi should hear it read by an Ashkenazi. If a Sepharadi normally prays in an Ashkenazic Minyan, he should make a point to attend a Sephardic Minyan for the reading of Parashat Zachor, and vice versa. There are several differences in pronunciation between the Sepharadim and Ashkenazim, such as the pronunciation of the Kamatz vowel. Sepharadim pronounce the Kamatz as a Patah, and thus, for example, they pronounce God’s Name as "Ado-NAI." Ashkenazim, however, pronounce the Name as "Ado-NOI." All year round, Halacha allows one to hear the Torah read according to a different custom, but since the reading of Parashat Zachor constitutes a Torah obligation, one should ensure to hear the reading pronounced according to his tradition. Indeed, the Hazon Ish (Rabbi Avraham Yeshaya Karelitz, 1879-1954) wrote a letter declaring that an Ashkenazi cannot fulfill the Misva of Zachor by hearing the section read by a Sepharadi.
It must be emphasized that both traditions regarding Hebrew pronunciation are valid and have ancient roots. This is not a question of which is correct and which is incorrect; rather, "Elu Ve’elu Dibreh Elokim Hayim" – both customs are legitimate are grounded in ancient Torah tradition. Sepharadim and Ashkenazim should follow their respective customs, and when it comes to Shabbat Zachor, every person should ensure to hear the reading from somebody who reads according to his family tradition.
Surprisingly, the Steipler Gaon (Rabbi Yisrael Yaakov Kanievsky, 1899-1985) wrote a letter asserting that the Sephardic pronunciation of the Kamatz is erroneous, and thus Sepharadim never recite Hashem’s Name properly and never fulfill the Misvot involving Berachot and the like. Needless to say, it is quite astonishing to claim that all Sepharadim never properly fulfill these Misvot. Indeed, Rabbi Mazuz wrote a lengthy responsum refuting the Steipler Gaon’s contention, and expressing his astonishment that somebody would advance such a claim. He cites numerous sources proving that Sepharadim have always pronounced a Kamatz as a Patah, and that this tradition is many centuries old. For example, Rabbi Shelomo Ibn Gabirol, in his rhyming Azharot hymn, writes, "Anochi Ado-nai, Keraticha Be-Sinai." He clearly intended for Hashem’s Name to rhyme with "Sinai," even though the final vowel in Hashem’s Name is a Kamatz, and the final vowel of "Sinai" is a Patah. This proves that he pronounced the two vowels identically. Similarly, Rabbi Yehuda Halevi wrote in the "Mi Kamocha Ve’en Kamocha" hymn which we sing on Shabbat Zachor, "Bi’ymeh Horpi Mi’kadmonai, Bi Diber Ru’ah Ado-nai." The word "Mi’kadmonai" – which ends with the Patah sound – is used to rhyme with Hashem’s Name. Likewise, in the famous "Sur Mi’shelo" hymn which we sing on Shabbat, the word "Emunai" – which ends with a Patah vowel – is used to rhyme with Hashem’s Name ("Sur Mi’shelo Achalnu Barechu Emunai, Sabanu Ve’hotarnu Ki’dbar Adon-nai"). These and other examples clearly testify to an ancient Sephardic tradition to pronounce the Kamatz as a Patah.
In his responsum, Rabbi Mazuz expresses his dismay that an Ashkenazic Sage would protest against Sephardic pronunciation, rather than addressing the problems that arise from the conventional Ashkenazic pronunciation. Ashkenazim generally make no distinction in their pronunciation between an "Ayin" and an "Alef," which yields very problematic results when pronouncing verses like, "Va’abatetem Et Hashem" ("You shall serve God"). If one pronounces the "Ayin" in "Va’abatetem" as an "Alef," then he ends up saying, "You shall eradicate God," Heaven forbid. This is a far graver concern than pronouncing Hashem’s Name as "Ado-nai" in accordance with a longstanding Sephardic tradition. Furthermore, Rabbi Mazuz notes, there were several great Ashkenazic Sages who adopted the Sephardic pronunciation because they felt it was more authentic. The Arizal (Rabbi Yishak Luria of Safed, 1534-1572), for example, was an Ashkenazi, and yet he adopted the Sephardic pronunciation and prayer text. And it is told that Rabbi Natan Adler of Pressburg (the teacher of the Hatam Sofer) hired Rabbi Haim Moda’i of Turkey, a Sepharadi, to teach him Sephardic pronunciation.
Thus, as mentioned, both traditions are valid, and everyone should use the pronunciation followed by his family’s tradition.
Summary: A Sepharadi should ensure to hear Parashat Zachor read in Sephardic pronunciation, and an Ashkenazi should ensure to hear Parashat Zachor read in Ashkenazic pronunciation.
