With the Croatian Catholic church records I've been studying, when the headings are in Croatian the written text is Croatian as well, and when the headings are in Latin, the written text is Latin. The church seemed to flip-flop through the decades between Croatian and Latin.

GoogleTranslate (translate.google.com) has been my best friend in translating these church records from both Croatian and Latin into English (well, sort of in the case of Latin, but the results are usually understandable).

So, when I type the characters of the 1st column heading of your record into GoogleTranslate (when it's set to auto-detect the language), it auto-detected and seems to translate successfully from Italian to English:

date of the wedding celebration and name of the parish priest who attended it

When I force it to translate from Latin to English it can't translate it all:

data della celebrazione del matrimonio e nome del parroco che vi ha assistito

Therefore, I would conclude that your records are written in Italian.

If you're doing much work with these kinds of records that somebody hasn't already translated, I urge you to learn to read the script and translate the records yourself. Reading the script becomes, at times, a task of handwriting analysis to determine how a particular writer wrote out individual letters. Having lots of word examples from the same writer (which you appear to have on this and subsequent records of this dataset) helps tremendously to decipher the writer's "hand". Sometimes even then you may get stuck on a particular word in a sentence. When that happens, I just start trying all combinations of possible alternative letters until the translation seems to make sense.

I hope this helps you get started. Cheers.