Hebrew pronunciation

Dear Rabbi: In modern Israeli Hebrew, several vowel pronunciations and consonantal variations, which exist in traditional Hebrew pronunciations (e.g. Ashkenazi, Spharadi, Yemenite), are not differentiated. How did this come about, and what are the implications for prayer and Torah study? I have noticed some confusion where Ashkenazi and modern Israeli pronuciations are used concurrently. Is there a benefit to maintaining traditional Hebrew pronunciations for prayer and Torah study, in the state of Israel and outside? Thanks

Shu”t Iggrot Moshe (Orach Chayyim III 5) teaches us that all accepted pronunciations of Hebrew are Halachically Hebrew- not because our forefathers at Mt. Sinai had more than one pronunciation, but because a language develops in this way with time. Even so each person should when davening to himself or when reading the Torah in a shul where everyone else came from the same place in Exile, prefer the pronunciation of his ancestors. This unless observing the custom of his fathers would cause a fracas or hurt his devotion when praying (see Orach Mishpat of Rav Kook 16, 17,18). A chazan should use the pronunciation accepted in the shul in which he is davening. Rav Ovadia Yosef writes that it is a mistake to think that in the Spharadi pronunciation a “Kamatz” and a “Patach” are identical- there is a subtle difference (Shu”t Yabiya Omer VI Orach Chayyim 11 (4)).