Was Israel of one language? Did the nation of Israel all speak the same language? Thank you.
Israelites spoke Hebrew. After the captivity, Aramaic was spoke a good bit and portions of the Old Testament are written in Aramaic. During Jesus' day, Aramaic was the common language and Hebrew was the "religious" language, so all Jews could speak both Hebrew and Aramaic. "Spoken in ancient times in Palestine, Hebrew was supplanted by the western dialect of Aramaic beginning about the 3rd century BC; the language continued to be used as a liturgical and literary language, however." ["Hebrew Language," Encyclopedia Britannica].
"A Short History of the Hebrew Language" by Jeff A. Benner makes for a good read on this topic.