I answered this question in some detail in this older thread. Scholars don't agree on whether speeches like this really happened. There is evidence to support either answer. The safest assumption is that they would have been very short, and probably delivered only to core troops or passed down to individual units by subordinate officers.

Here’s a recent post in this sub asking this, and it links to further posts with some answers. Hope that helps while you wait on more replies.

edit: let me add the user names of the commenters there, as per the rules! Just got a message about that. Thanks for your patience!

edit 2: commenters tagged from previous posts -

so /u/knoperope lists “Do the speeches we often see before a battle in most literature and visual performances have any historical basis. Did the kings and generals leading an army ever give a speech to rally the troops. Or is this just a modern romanticism?” (featuring u/Thrasyboulus, u/Celebreth, and u/Quiets)

and

“Did great military generals and leaders give speeches before battles like you see in the movies? And if so, were only a few able to hear it?” answered detailed by /u/XenophonTheAthenian

in the post I’ve linked directly, which was made by /u/Tillidsmanden

If there’s anything I’ve missed please let me know!