Chapters 1 and 8-12 of The Book of Daniel are written in Hebrew like the rest of The Hebrew Bible. But Chapters 2-7 are in Aramaic. Aramaic is also a Semitic language, it uses many seemingly identical words, but they are still distinct.
A difference in focus and subject matter also exists between these two parts of Daniel. The popular conjecture which I agree with is that Hebrew Daniel is focused on History and Prophecy from a Jewish perspective. While Aramaic Daniel still has Jew as it's protagonists and presumes the Monotheistic Jewish religious worldview to be true, but is much more then most parts of The Hebrew Bible focused on the Gentile World and it's history.
Chris White expresses skepticism of this way of looking at Daniel. He thinks it could be true, but his skepticism of the assumption is mostly just based on observing that Gentile nations are still discussed in Hebrew Daniel.
The point is the more rigidly Jerusalem/Judah POV. 4 or 5 different Kingdoms emerged from the dividing of Alexander's Empire. Why are only two really discussed in most of Daniel 11 (King of the South=Ptolemaic Egypt and the King of The North=Seleucid Syria). Because they're the two that had Jerusalem in the disputed territory between them. So even if Daniel 11's description doesn't always seem to mention Judah's role in those wars in the text, rest assured they always had a direct impact on Judah.
The Hebrew Chapters largely revolve around Jerusalem and The Temple. The Aramaic chapters barely if at all mention Jerusalem's existence, and never The Temple. The Prophetic parts of Hebrew Daniel always involve The Abomination of Desolation, or things linked to it like the offerings being stopped. Aramaic Daniel doesn't bring up that subject at all.
The four world Empires theme comes entirely from Aramaic Daniel. Hebrew Daniel backs up this way of looking at history, but in a way that requires reading between the lines. It is also only Aramaic Daniel that records Daniel's personal relationships with world leaders. In Daniel 1 he only gets to know as high up a the chief Eunuch.
It's interesting to look at the agenda of Bible Skeptics when it comes to Daniel. Any other book they love pointing out reasons to question if the whole Book really had the same Author, like Isaiah. Here however it's a Book written in different languages but they don't want to do that, why?
Because it's Aramaic Daniel that has all the historical references (that they claim are errors), and the three random Greek musical instruments they use as scholarly reasons to back up their late dating.
But it's Hebrew Daniel that has the really detailed specific future Prophecies they want to insist must have been written later. So it does not suit them to break this book up, though they could make a much stronger case for it then Isaiah.
And arguing the Aramaic is the older part would go greatly against other narratives they promote. About Hebrew dying out and being supplanted b Aramaic.
Only Hebrew Daniel gives names to Angels. Michael and Gabriel.
Aramaic Daniel used titles for God and The Messiah unique to it in the entire Canonical Hebrew Bible. Intertestamental Apocrypha like Enoch began merging ideas from the two parts of Daniel. And The New Testament draws on Aramaic Daniel as much as it does I feel precisely because of the theme of Gentile inclusion.
"The Ancient of Days" is one such unique title. I personally feel this title is specific of The First Person of The Trinity, at least somewhat, or used to anyway, I've been rethinking that. It is also only Daniel 7 that has Son of Man as a Messianic Title. In other Prophets it's a term for any human being. In The Gospels this is Jesus favorite title for himself.
Aramaic Daniel does not use the term Messiah, that term was originally specific to the Jewishness of Jesus.
Daniel 7 and 8 are where Hebrew and Aramaic Daniel are most similar to each other. Both envision Gentile Empires as Beasts, and having a "Little Horn" as the Villain of the End Days. The two Beasts of Daniel 8 equate to the 2nd and 3rd Beasts of Daniel 7.
But what kinds of Animals are used for the beasts reflects the change from a Gentile to Jewish perspective. In Daniel 8 they're Levitically clean animals (a "Ram" and a Goat), going over Numbers 28-29 shows that both were regularly offered in The Temple on New Moons and Holy Days. While the three identified animals of Daniel 7 are all unclean, and also carnivorous. Outside Daniel they are still animals that can be used symbolically, but when contrasted in how Daniel is divided, they reflect 7 being less Levitical then 8 at the very least.