In this episode, we read a responsum by Rabbi Yechiel Yaakov Weinberg, an eminent 20th-century Orthodox authority, on our question. Weinberg is candid enough to admit that the reformers who introduced vernacular prayer back in the 1800s had a powerful halakhic argument to support then. He indicates, as well, that the Hatam Sofer’s creative halakhic theory forbidding prayer in the vernacular (episode 3 in this series) does not really prove the reformers wrong. But he goes on to forbid the introduction of the vernacular into the synagogue service for other, non-halakhic reasons. It’s a good example of how supposedly “non-halakhic” considerations often influence the way that rabbis read the law. The question: which reading - the "reform" or the "orthodox" - is the better one?