One may recite the Amida in any language (Sota 32a). However, it is best to pray in Hebrew, for that is the language in which the Men of the Great Assembly composed the prayers. Furthermore, Hebrew is the holy tongue and is the language with which the world was created.
An additional advantage to praying in Hebrew, untrue of any other language, is that one may pray in Hebrew even if she does not understand it. As long as she understands the first verse of Shema and the first berakha of the Amida, she fulfills her obligation. In any other language, only one who understands what she is saying fulfills her obligation (MB 101:14 and 124:2).
In practice, one who does not understand Hebrew may choose the language in which to pray. On one hand, there is an advantage to praying in a language that she understands, for it enables her to have more kavana. On the other hand, if she prays in Hebrew, she prays in the holy tongue (see BHL 101:4; Kaf Ha-ĥayim 16). 1
Permission to pray in other languages is granted only as a temporary measure (hora’at sha’ah), specifically for people who do not understand Hebrew. However, it is prohibited to organize a minyan of people who pray regularly in a different language. That was one of the sins of the Reform movement, which translated the prayers to German and caused their children to forget the holy tongue, leading the way to assimilation and the abandonment of Judaism (Ĥatam Sofer, OĤ 84 and 86; MB 101:13).
- Indeed, according to Rif, only one who is reciting the Amida with a minyan may pray in another language. The reason for this is that the divine Presence dwells within a minyan; therefore her prayer will be accepted even if it is not in the holy tongue. However, the prayer of one who prays alone in a different language is not accepted. Nevertheless, most poskim agree with Rosh, who maintains that even one praying alone may pray in another language, as long as it is not Aramaic. This is the halakhic ruling (SA 101:4, based on the rule that the halakha follows the last “yesh omrim,” MB 18). ↩