A similar question arose among Ashkenazic immigrants from the dati-leumi (national-religious) community. Approximately three generations ago, with the beginning of the gathering of the exiles, a need was felt to consolidate the Diaspora communities and to restore the Jewish nation to its Hebrew language. For unification purposes, the Sephardic pronunciation was chosen. Even though Maran HaRav Kook ztz”l, and many other poskim, are of the opinion that each ethnic group must preserve its own accent in prayer, in actuality, since the spoken Hebrew and the Hebrew learned in schools were in a Sephardic pronunciation, the Sephardic accent became imbedded in the prayer service too. Indeed, many leaders of national-religious educational institutions, acting in accordance with the rulings of a few rabbis, instructed their Ashkenazic students to pray with Sephardic pronunciation.
There are some rabbis who spoke strongly against the Ashkenazim who changed their accent. Some taught that even people who find it difficult to pronounce all the prayers in an Ashkenazic pronunciation should at the very least pronounce Hashem’s Name in that manner, because the pronunciation of Hashem’s Name in the Ashkenazic accent has greater grammatical advantages (Har Tzvi Orach Chaim 1:4; Az Nidberu, part 3, 48:1, according to the Chazon Ish).
However, in practice, most rabbis do not encourage their students to change their pronunciation. Since the Sephardic accent is just as acceptable as the Ashkenazic, and everyone is used to it, there is no obligation to return to one’s original accent. Moreover, if the effort to change one’s pronunciation will disrupt his kavanah in prayer, it is preferable not to change it. It is best that one who already prays in a Sephardic accent also say Hashem’s Name that way so as not to mix accents. There are even those who are concerned that one who combines accents b’dieved does not fulfill his obligation (Rav Yosef Henkin; She’arim Metzuyanim BaHalachah 18:5). Therefore, it is customary to recite the whole prayer service, including Hashem’s Name, in the Sephardic accent.
. Mishpatei Uziel, Orach Chaim 1, maintains that it is proper for all the ethnic groups to pray in a uniform nusach and accent. Maran HaRav Kook commented on this, saying that every ethnic group must preserve its own minhagim. He continues that one who changes his accent is considered like “one who recited [the Shema] and was not meticulous in enunciating the letters,” for even though he fulfills his obligation, he should not do so l’chatchilah. That is the opinion of most rabbis, among them Minchat Yitzchak 3:9, and 4:47, 4, and Az Nidberu, part 3, 48:1. However, a number of Sephardic rabbis, including Yaskil Avdi, part 2, Orach Chaim 3, and Yabia Omer, part 6, Orach Chaim 11, write that an Ashkenazi is permitted to switch to the Sephardic accent. They praise the Sephardic nusach and note that since it is spoken today in the Holy Land, it is therefore proper to pray in it. However, it is noteworthy that the spoken accent today is less precise than the original Sephardic accent, for today’s spoken accent does not differentiate between a tet and a taf, between a kuf and a kaf degushah, between a tafdegushah and a taf refuyah, or between a kamatz and a patach. From a certain standpoint, it is the worst of all the pronunciations, for it does not have the virtues found in the Ashkenazic dialect, and it is missing a few of the advantages present in the Sephardic dialect. Nevertheless, Yabia Omer does not comment on this.In any case, after people have already become accustomed to the Sephardic accent, even according to those who maintain that in principle one must revert to his family’s nusach, if it is difficult to do so, and it will disrupt one’s kavanah, one need not revert to the Ashkenazic nusach. That is what my teacher and rabbi, HaRav Tzvi Yehudah HaKohen Kook, ztz”l, maintained. Furthermore, he mentioned that there are things which are accepted by the community even though the Chachamim are not pleased with them. He also said that something good comes out of this: members of different ethnic groups can pray together, and unity is increased.
The Yabia Omer 11:6, quotes Rabbi Unterman, the Ashkenazic Chief Rabbi of Israel, in saying that the Ashkenazim who became accustomed to praying in the Sephardic accent should not be compelled to revert to the Ashkenazic pronunciation. That is how they were educated and they are comfortable in this accent, because it is widespread throughout the whole country. The Yabia Omer adds that it is preferable that they pray in the spoken dialect, for in that way the youth will feel more of a sense of belonging to the synagogue and the prayer service. One may add that even if a person stands before a king, he will talk in the accepted dialect, and he will not begin to precisely pronounce the letters. We learn many of the laws of prayer from an individual who stands before a king using the kal vachomer principle.