As the romans as a civilisation lasted many centuries it makes sense that the language would have changed significantly over that time.
I am wondering if the latin we see today is the last incarnation of the roman language used by the empite or whether its the latin used at the height of Rome's power from which there is likely to be a greater amount of written examples.
Bonus question. As a lot of western European languages are derived from latin. When did latin as a language stop being considered the language being spoken.
Edit: western not eastern
Most introductory Latin textbooks will present examples from throughout Latin's usage. Ideally, it will equip you with the skills to read any of them, provided a little glossing of timely idioms. The Wheelock's Latin textbook on my shelf has samples of:
The language does change during the reign of the empire, but not enough to have to teach separate "Latins." Jerome and Cicero are rather different, but so are Shakespeare and Austen and Hemingway, and you can find all three of those in the same English class. In any more specialized Latin class, focus will be given to how the author's language reflects the time. Later Medieval Latin authors, like Bede, do require a little additional background study, but far less than one would need for reading English from 800 years ago. Latin was primarily preserved as a literary language, which is less prone to the evolutionary tendencies of spoken languages.
Generally, you can consider it to being developed from a form from around the first century BCE. However more specifically it was not one variety. It's just that around that time period it began to solidify a bit more. In fact it began to be standardises before then, in the third and second centuries BCE. Obviously it underwent minor changes throughout the following part of Rome's history, but they were still changes within this previously established framework. Still, it took different forms at different times, just like other classical languages used in similar contexts in the past.
Despite this, it doesn't really change as much as you might think. Like many historically similar situations in large nations/empires/spheres-of-influence around the world, it represented a sort of ideal form of the language. In the case of Latin, it was form from this earlier period in Rome's history, and was based on the language of Rome's urban elites. As such it was also intentionally conservative for features but innovative in terms of vocabulry based on a need for the language to expand into its role as lingua franca.
Someone asked a related question recently which specifically asked about the instanced of bilingualism in Roman society as this time, which I responded to here. You might want to take a look at that for a bit more background information on this time period's linguistic situation.
Source: