If a Jewish man does not understand Hebrew, is he required to pray while attending services?
Answer:
Yes. Somebody who does not understand Hebrew should pray in the language he speaks and understands. Prayer in a foreign language is a valid form of prayer. Over time, it is preferable to learn the Hebrew tongue, and to pray in the original Hebrew, which has a special virtue.
Sources: See Shulchan Aruch, Orach Chaim 101:4, and Mishnah Berurah.
