The Talmud and various Jewish commentaries address this question, and there are different opinions. Here's a breakdown of the main perspectives:
* One Language - Hebrew: This is the most straightforward interpretation of the text. The Torah was given in Hebrew, the language of the Israelites.
* One Language - All Languages: Some Midrashic sources state that God's voice was heard in all 70 languages of the world simultaneously, so that everyone could understand.
* One Language - Aramaic: In ancient times, Aramaic was the vernacular language of many Jews, even if Hebrew was used for religious purposes. Some posited that the spoken revelation was in Aramaic for better comprehension.
Conclusion:
While the straightforward reading of the text suggests Hebrew, various interpretations try to grapple with the idea of a universal revelation, accessible to all. Some suggest the voice was heard in all languages, emphasizing the inclusivity of the divine message.