What is the difference between Classical and Ecclesiastical Latin?  What is Classical and what is Ecclesiastical?

Ecclesiastical is the Latin used by the church, namely the Catholic Church.  It has been used for ages past (and in some cases still used today)in the mass which is the religious service of the Catholic Church.

Classical is the Latin used by students who are studying Latin,  This the Latin taught at major universities, and what is used in Latin competitions all across the country called " Certamen Latin".

There seems to be a big discussion about the difference between these two.  Actually there is no difference when you are reading to yourself or writing.
The difference comes when you read aloud or chant things.  It is the pronunciation which differs between these two.

Some specific differences are the pronunciation of "g" and "c".  The largest difference is this:  In Ecclesiastical Latin these are pronounced soft as in "George" or "giraffe" and "city" or "citizen".  In Classical Latin these are nearly always pronounced hard as in "garden" and "good" or "cat" and "collie".  There are a list of rules which dictate some other details of pronunciations,  but too long to go into here.

Realizing these slight differences, it doesn't seem worth an argument of which is the right way to "speak" Latin.  If however, you plan to go on in your studies or enter a Certamen, you may want to consider using the Classical way.

In the end, all is not lost if you choose one and your best friend uses the other.  You can still write notes to each other and understand it just fine!

Have a great day.
m.e.