We know that the bible is very old and has had multiple translations and re-writings over the years. For the new testament, it was written in medieval greek and the documents were well preserved and copied. But the old testament, at least as close as we can get to primary sources, were written in Ancient Hebrew and Aramaic among other things. How were theologians and historians able to understand languages that nobody spoke and translate/codify them into the book we know today? Are today's writings an accurate translation or have we gotten lost playing a game of ancient biblical telephone?
You seem to be under several misapprehensions...
The Bible is not a series of serial translations and re-writings. There's no sense in which, e.g. it was translated X > Y > Z and X or Y are lost versions. The New Testament is written in Koine Greek, which is standard Greek for the 1st century context of where and when it was written. Nobody would call this 'medieval' Greek. Yes, it was preserved and copied.
The Hebrew Bible (/Old Testament) was, at least in its literary form (excluding possible prior oral circulations) composed in Hebrew and Aramaic. But there's no point at which there wasn't a living community that transmitted and understood those writings. Note, I'm not saying that those languages continued to be spoken in those precise forms. But certainly among Jewish communities, knowledge of Hebrew (and Aramaic) was not 'lost', there is not a "gap" and "rediscovery" here, except if you isolate that to particular communities (e.g., knowledge of Hebrew was never prevalent among western Europe, but it did start to spread in post-Reformation Europe as Protestants considered the Hebrew version of the Old Testament to hold canonical status, and so deliberately sought to learn Hebrew from contemporary Jewish scholars).
Yes, there are parts, linguistically speaking, of the Hebrew Bible that remain obscure. Plant and animal names spring to mind. But those aren't recent obscurities, they are ancient ones.
How were theologians and historians able to understand languages that nobody spoke
People spoke them and knowledge of them was transmitted over time
and translate/codify them into the book we know today?
Bible translators work with the original languages to translate them into contemporary languages
Are today's writings an accurate translation
Yes, the quality of today's translations is quite high.
or have we gotten lost playing a game of ancient biblical telephone?
No, because this idea of serial transmission / rewriting / multiple translation / gaps of knowledge and rediscovery are basically misrepresentations of the situation.