|"Is this all real? Or has this been happening inside my head?"
The topic of this article is of a real-life subject that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really exists), and, as such, details contained in this article may differ from real world facts.
Hebrew is a Semitic language, originally spoken in the ancient Levant. It died out as a spoken language around the 3rd century B.C., being replaced by Aramaic, but continued to be used for religious and cultural purposes by Jews. It was eventually revived as the official language of Israel in the 20th century.