Ran across this quotation in the introductory chapter to Botanical Latin, Wm. T. Stearn-

Sic enim potius loquamur: melius est reprehendant nos grammatici quam non intelligant populi.
Let us rather than declare: it is better that the grammarians censure us than that the public does not understand us.
St. Augustine of Hippo (A.D. 354-430) Ennar. in Psalm, cxxxviii, 20

In discussing botanical Latin, Stearn says: ".....it is so far evolved that it is almost as different from classical Latin as modern from Chaucerian English."
The same is true of church and other modified forms of Latin, which owe much to Renaissance Latin.

Roman pronunciation- MtheGM is correct, we have no real knowledge of the pronunciations of the times- I say pronunciations, because we are told, and examples show, that the educated Roman and the common man spoke widelly different versions of the language.
Nor do we know how the spoken roots of other modern languages were pronounced or sounded.