Hebrew is a root-based language, which means that words are built around a root word or concept. This makes it a pretty concise language, with a lot of words packing a big punch in just a few letters. For example, the Hebrew word for "love" is related to the word for "give", which is pretty cool when you think about it!
But Aramaic also makes an appearance in the Old Testament, particularly in the books of Daniel and Ezra. Aramaic was like the lingua franca of the ancient world, spoken by people from all over the region. It's no surprise that it shows up in the Old Testament, given its importance in the ancient world.
